Question:
I just moved and now live next to a creek. I plan to build a new pond soon and I would like to use the water from the creek. I think I have thought the pros & cons through, but I am not sure. We are 20 feet above the creek, so no flooding. We have rights to the water, no problem there. Salmon come up the creek to spawn, so the water should be good? There are steelhead here also, so does that say the water is ok? The previous owner lowered a pump into the creek during the summer months and turned it on daily to water the flower beds & trees. I was thinking of tapping into that line and add fresh water everyday to the pond, allowing any extra to overflow somewhere/somehow. The new pond will be approx 3000 gallons, how much water would be too little or too much to add daily? Any advise/suggestions anyone can offer would be greatly appreciated. — -Wendy in CA
Response:
A friend of mine did almost the same thing, but feeds from a canal, then lets overflow run by "river" back to canal with mouth of river blocked by a wall of rocks to keep fish in. He uses a separate pump to run waterfall , with no filter, justs flushes pond daily from canal . His water is not crystal clear like a totally contained system with a bio-filter, but not too bad the 3 times I saw it – as clear as the water in the canal I guess at 3′ depth Gale – Hide quoted text — Show quoted text -> I just moved and now live next to a creek. I plan to build a new pond soon > and I would like to use the water from the creek. I think I have thought > the pros & cons through, but I am not sure. We are 20 feet above the creek, > so no flooding. We have rights to the water, no problem there. Salmon come > up the creek to spawn, so the water should be good? There are steelhead > here also, so does that say the water is ok? The previous owner lowered a > pump into the creek during the summer months and turned it on daily to water > the flower beds & trees. I was thinking of tapping into that line and add > fresh water everyday to the pond, allowing any extra to overflow > somewhere/somehow. The new pond will be approx 3000 gallons, how much water > would be too little or too much to add daily? Any advise/suggestions anyone > can offer would be greatly appreciated. > — > -Wendy in CA
Response:
It’s certainly fine to use good creek water to fill or top off the pond. But it might not be desirable to do daily water changes with it? It might be very low in alkalinity, hardness and plant nutrients, especially after rains when it might also be turbid. If it’s colder than the pond, it’ll slow down growth of both fish and plants. . The current trend in pond aquaculture is away from even annual water changes, to good biofiltration and reuse of the same water year after year. This study shows that water change results in no improvement in fish growth or productivity, it simply removes nutrients from the pond. http://ag.ansc.purdue.edu/aquanic/publicat/usda_rac/efs/srac/600fs.pdf My wife’s first pond is the same size as yours, and the first water change, just to clean out the bottom, was done after five years. – Rod
Response:
> The current trend in pond aquaculture is away from even annual > water changes, to good biofiltration and reuse of the same water > year after year. This study shows that water change results in > no improvement in fish growth or productivity, it simply removes > nutrients from the pond.
http://ag.ansc.purdue.edu/aquanic/publicat/usda_rac/efs/srac/600f s.pdf But Rod, removal of nutrients is, for most of us, a Good Thing. Most of us aren’t doing aquaculture. I’d agree with you if it wasn’t for the fact that most of us have too _many_ nutrients, not too few. If you flush out all the unknowns, then you can take care of plants with addition of fertilizer and the fish with pellets. — Derek (www.netcom.ca/~dbrought/pond) rec.ponds FAQ http://w3.one.net/~rzutt/faq.html Those who make peaceful revolution impossible will make violent revolution inevitable – J.F. Kenn
Response:
Thanks for the responses. They give me more to think about . I was planning on adding a just a few gallons, enough to top it off and spill out some. I was thinking on still having a veggie filter (100 gal Rubbermaid), gotta give the dragonflies a safe place to breed! The creek does get cloudy after a rain, but we have no rain here from April to October, the months I would be adding water. During the winter, if needed, I could top it off with well water? Ps, I am so excited about the thought of finally having frogs in the pond! — -Wendy in CA
Response:
– Hide quoted text — Show quoted text ->It’s certainly fine to use good creek water to fill or top off the pond. >But it might not be desirable to do daily water changes with it? >It might be very low in alkalinity, hardness and plant nutrients, >especially after rains when it might also be turbid. If it’s colder >than the pond, it’ll slow down growth of both fish and plants. >.. >The current trend in pond aquaculture is away from even annual >water changes, to good biofiltration and reuse of the same water >year after year. This study shows that water change results in >no improvement in fish growth or productivity, it simply removes >nutrients from the pond. >http://ag.ansc.purdue.edu/aquanic/publicat/usda_rac/efs/srac/600fs.pdf >My wife’s first pond is the same size as yours, and the first water >change, just to clean out the bottom, was done after five years. >- Rod
Know your source water (to paraphrase what Rod’s got to say). I use mostly creek water, pump it up at about 350,000 gph. It is mostly good water. It goes to my reservoir of about 50 million gallons. I use reservoir water directly through my holding facility, one time through, then out. Rod is mostly right with respect to aquaculture water, in some systems. However, in sourthern ponds with extemely dense populations, especially catfish, tilapia, or striped bass, the water gets more than nutrients in it and has to be changed frequently. I worked for many years on a catfish farm where we did it a bit different. We did have biofiltration systems. Each system about 200 acres, with about 10 ponds, and two biofiltration ponds. Each fish pond changed out once in 9 days, each biofilter pond twice each day. Our "filters" were fish. We used several species, but some of the best were bighead carp (Aristichthyes nobilis), silver carp (Hypothalmichthyes nobilis), and paddlefish (Polyodon spathula). These fish actually filter the water for detritus and algae, through thier gills, converting nutrients into fish flesh while preparing the water to be returned to the catfish ponds. We achieved system wide production rates of over 25,000 pounds per acre when the industry average was about 3000 pounds per acre. Many similar type systems are in operation today. Just like a koi pond, except hundreds of acres and hundreds of millions of gallons. I’ve not been to the "aquanic" site in awhile, think I’ll go check it out. Got a lot of my fish living at Purdue (blue catfish). Never been there myself. Brett
Response:
>But Rod, removal of nutrients is, for most of us, a Good Thing. >Most of us aren’t doing aquaculture. I’d agree with you if it >wasn’t for the fact that most of us have too _many_ nutrients, >not too few.
A pond with a balance of fish, plants and biofiltration won’t accumulate "too many nutrients". (In a desert, it might eventually accumulate too much hardness or salts. But most areas get enough rain that isn’t a problem.) Indeed, rivers and streams may have more nutrients than a balanced pond does. This is true of most rivers in my area: http://www-va.usgs.gov/chesbay/RIMP/ In a pond, we ideally want higher alkalinity and salinity than most water sources provide. Water changes remove these, and may add nutrients which trigger algae blooms. For example, after a rain, my local river goes down to pH 6.5, KH 10 mg/l, salinity ~0 ppm. In a dry spell, it rises to pH 7.6, KH ~50 mg/l, salinity >50 ppm. It’s flow and turbidity vary by a factor of ~100. Local streams vary even more than the river, by a factor of up to 1000 in flow and turbidity, with pH ~ 6 and KH ~ 0 during a rainstorm. In spring, they have an excess of phosphate which will trigger an algae bloom when warmed in a sunny pond. By late summer, phosphate is ~0.1 ppm in the river, but may remain high in shady streams that receive runoff. It’s constantly changing, but its alkalinity and salinity are always lower than we want in the pond. On the other hand, "Ponds may be operated for multiple years without draining with no decrease in fish production attributable to deterioration in environmental conditions within the pond." Conclusion on page 20 of: http://ag.ansc.purdue.edu/aquanic/publicat/usda_rac/efs/srac/600fs.pdf It isn’t clear that water changes are beneficial. – Rod
Response:
I have no question about the engineering, but you have not addressed the problem of mixing wild and domestic water. You didn’t say what kind of fish you are looking to keep, but it is usually not a good idea to mix stuff, like plants, taken from the wild in with your fish. You may think the water — Todo — North Florida Koi Club, – Hide quoted text — Show quoted text -> I just moved and now live next to a creek. I plan to build a new pond soon > and I would like to use the water from the creek. I think I have thought > the pros & cons through, but I am not sure. We are 20 feet above the creek, > so no flooding. We have rights to the water, no problem there. Salmon come > up the creek to spawn, so the water should be good? There are steelhead > here also, so does that say the water is ok? The previous owner lowered a > pump into the creek during the summer months and turned it on daily to water > the flower beds & trees. I was thinking of tapping into that line and add > fresh water everyday to the pond, allowing any extra to overflow > somewhere/somehow. The new pond will be approx 3000 gallons, how much water > would be too little or too much to add daily? Any advise/suggestions anyone > can offer would be greatly appreciated. > — > -Wendy in CA
Response:
> I was thinking of tapping into that line and add >fresh water everyday to the pond, allowing any extra to overflow >somewhere/somehow. The new pond will be approx 3000 gallons, how much water >would be too little or too much to add daily?
We have a club member here with a 3500 gallon spring fed concrete lined koi pond. She would like the water to be more clear, but the addition of nutrients from the flowing water usually keep the water in stages of green. Regards, Hal
Response:
- Hide quoted text — Show quoted text -> The current trend in pond aquaculture is away from even annual > water changes, to good biofiltration and reuse of the same >water year after year. This study shows that water change results in > no improvement in fish growth or productivity, it simply >removes nutrients from the pond. >http://ag.ansc.purdue.edu/aquanic/publicat/usda_rac/efs/srac/600f >s.pdf >But Rod, removal of nutrients is, for most of us, a Good Thing. >Most of us aren’t doing aquaculture. I’d agree with you if it >wasn’t for the fact that most of us have too _many_ nutrients, >not too few. If you flush out all the unknowns, then you can take >care of plants with addition of fertilizer and the fish with >pellets.
Not to mention lowering the bacteria and parasite levels. I wonder what the experts who write for KOI USA would say about the above publication? Concerning your wife’s pond, didn’t you say the area where you live receives a goodly amount of natural rain fall? If so, there’s your water change if that’s the case. Whereas those in the desert areas …… ;o) ~ jan
Response:
– Hide quoted text — Show quoted text ->But Rod, removal of nutrients is, for most of us, a Good Thing. >Most of us aren’t doing aquaculture. I’d agree with you if it >wasn’t for the fact that most of us have too _many_ nutrients, >not too few. >A pond with a balance of fish, plants and biofiltration won’t >accumulate "too many nutrients". >(In a desert, it might eventually accumulate too much hardness >or salts. But most areas get enough rain that isn’t a problem.) >Indeed, rivers and streams may have more nutrients than a >balanced pond does. This is true of most rivers in my area: >http://www-va.usgs.gov/chesbay/RIMP/ >In a pond, we ideally want higher alkalinity and salinity than most >water sources provide. Water changes remove these, and may >add nutrients which trigger algae blooms. >For example, after a rain, my local river goes down to pH 6.5, >KH 10 mg/l, salinity ~0 ppm. In a dry spell, it rises to pH 7.6, >KH ~50 mg/l, salinity >50 ppm. It’s flow and turbidity vary by >a factor of ~100. Local streams vary even more than the river, >by a factor of up to 1000 in flow and turbidity, with pH ~ 6 and >KH ~ 0 during a rainstorm. >In spring, they have an excess of phosphate which will trigger >an algae bloom when warmed in a sunny pond. >By late summer, phosphate is ~0.1 ppm in the river, but may >remain high in shady streams that receive runoff. >It’s constantly changing, but its alkalinity and salinity are always >lower than we want in the pond. >On the other hand, "Ponds may be operated for multiple years >without draining with no decrease in fish production attributable to >deterioration in environmental conditions within the pond." >Conclusion on page 20 of: >http://ag.ansc.purdue.edu/aquanic/publicat/usda_rac/efs/srac/600fs.pdf >It isn’t clear that water changes are beneficial. >- Rod
Those guys are not raising many fish in those ponds. Sure, with a standing crop of less than 1500 pounds per care, the pond can be in production for a long while. With the amounts of biomass in southern ponds (nowadays upwards of 10,000 pounds per acre) the pond must be drained, dried, bulldozed, limed, and refilled with fresh water at least once every four or five years. I do my ponds twice a year, at least. Also of extreme import to the pond’s usefulness in aquaculture is its ability to provide fish that "taste good". If the pond is not in good condition, it will show up in the flavor of the fish produced in it. This is of much greater economic importance than actual ability to produce fish flesh. If they don’t pass muster in the taster’s kitchen, they don’t get harvested, processed, and sold. Consider the loss in raising a bunch of fish you can’t sell because they taste bad. "off flavor" is the biggest problem facing modern aquaculturists today, more than disease, more than bad water quality, more than labor problems, etc. Not having the time to do it myself, see if there might be something with respect to southern aquaculture out there. The "Guru" of warmwater fish ponds is Dr. Claude Boyd. His book "Water Quality in Warmwater Fish Ponds" is the "Bible" of water quality in the South. He’ll be the first to tell you that you can indeed "wear the wet" out of fish pond water. Brett
Response:
>I have no question about the engineering, but you have not addressed the >problem of mixing wild and domestic water. You didn’t say what kind of fish >you are looking to keep, but it is usually not a good idea to mix stuff, >like plants, taken from the wild in with your fish. You may think the water
Of even greater concern is the possibility of pathogens. To keep out unwanted fish, I filter my "live water" through a 100 micron sock as I impound it into fish ponds. This keeps out unwanted fish and eggs. When I worked on the big catfish farm, we used water from the Brazos River to fill ponds. We raised lots of fish in that water. I still do at my "real job" at the bass fishing resort. We impound river water at the rate of 80,000 gph for 300 acres of fishing lakes and 15 acres of hatchery ponds. Of late, we had to stop taking river water due to high salinity (over 15 ppt or half seawater strenght). When I called the river authority to complain (we pay for that water), they told me to "check my contract", they only gaurantee "quantity". Makes me wonder what folks around there are drinking. Brett – Hide quoted text — Show quoted text ->– >Todo — North Florida Koi Club, > I just moved and now live next to a creek. I plan to build a new pond >soon > and I would like to use the water from the creek. I think I have thought > the pros & cons through, but I am not sure. We are 20 feet above the >creek, > so no flooding. We have rights to the water, no problem there. Salmon >come > up the creek to spawn, so the water should be good? There are steelhead > here also, so does that say the water is ok? The previous owner lowered a > pump into the creek during the summer months and turned it on daily to >water > the flower beds & trees. I was thinking of tapping into that line and add > fresh water everyday to the pond, allowing any extra to overflow > somewhere/somehow. The new pond will be approx 3000 gallons, how much >water > would be too little or too much to add daily? Any advise/suggestions >anyone > can offer would be greatly appreciated. > — > -Wendy in CA
Response:
>Those guys are not raising many fish in those ponds. Sure, with a standing >crop of less than 1500 pounds per care, the pond >can be in production for a long while. With the amounts of biomass in >southern ponds (nowadays upwards of 10,000 pounds per >acre) the pond must be drained, dried, bulldozed, limed, and refilled with >fresh water at least once every four or five >years. I do my ponds twice a year, at least.
They were producing about 6000 kg/ha (5300 lbs/acre) of 1 pound channel catfish. See Table 6 on page 19: http://ag.ansc.purdue.edu/aquanic/publicat/usda_rac/efs/srac/600fs.pdf Their levee ponds had an average depth 3 feet, so that’s an annual production of 1 lb/200 gallons, which is higher than a typical garden pond. (Of course, carp aren’t catfish!) – Rod
Response:
>see if there might be something with respect to southern >aquaculture out there.
This study was done in Alabama at Auburn University. – Rod
Response:
>Concerning your wife’s pond, didn’t you say the area where you live >receives a goodly amount of natural rain fall? If so, there’s your water >change if that’s the case. Whereas those in the desert areas ……
On average, we get 41 inches, pretty evenly though all 12 months. Average depth is 4 feet. The pond does overflow in winter and spring, so rain probably does exchange about 1/3 of it’s volume per year. The study I mentioned also tried lowering the pond, so rain did not cause overflow. Again, no change in water quality, no loss in growth or productivity, after 3 years. But most of us wouldn’t want to let our garden pond get a foot low by the end of summer. In our second pond, I lined the sides so it can drop 6" without exposing the liner. That helps! – Rod
Response:
– Hide quoted text — Show quoted text ->Those guys are not raising many fish in those ponds. Sure, with a standing >crop of less than 1500 pounds per care, the pond >can be in production for a long while. With the amounts of biomass in >southern ponds (nowadays upwards of 10,000 pounds per >acre) the pond must be drained, dried, bulldozed, limed, and refilled with >fresh water at least once every four or five >years. I do my ponds twice a year, at least. >They were producing about 6000 kg/ha (5300 lbs/acre) of 1 pound >channel catfish. See Table 6 on page 19: >http://ag.ansc.purdue.edu/aquanic/publicat/usda_rac/efs/srac/600fs.pdf >Their levee ponds had an average depth 3 feet, so that’s an annual >production of 1 lb/200 gallons, which is higher than a typical garden >pond. (Of course, carp aren’t catfish!) >- Rod
Did they say how they tasted? In densely stocked catfish ponds with little or no water exchange, the catfish get what the tasters call "sewage off flavor", one of the worst. Our taster could discern over 100 distinct off flavors. She taught me a great deal about the subject. Each morning after the samples had been brought to the taste kitchen I’d show up for the data sheet and for breakfast. She would keep the "good samples" for me which I put a bit of lemon pepper and salt on, then ate. The sampler would catch the fish from the pond to be sampled, usually two or three, cut the tail off at the vent, put in a baggy with a lable, then bring it to the kitchen. The taster would put the sample in a brown paper lunch bag and microwave (with no seasonings) for 6 minutes. She (tasters I knew were all female, don’t know why) would break open the bag and sniff, if it smelled bad, she marked it failed and threw it away. If it smelled OK, she would put some in her mouth, chew it a bit, and spit it out. If it passed, it was marked on the sheet. If it failed, it was ranked as how bad and why on the data sheet. I learned that the fish taste was a continuum, not a "good or bad" type thing. Some off flavors were easier to contend with than others. Some only required three or four days of "depuration" in a freshwater holding tank. Others took months to get rid off. In almost every case, a water change was prescribed. Some of the more common off flavors we had and why: Sewage-bad water muddy/musty-blue green algea bloom woody-tannic acid diesel-fuel spill cardboard-brown or red algae bloom soil or dirt-green algae bloom chemical-chemical spill, caught too soon after therapuetic treament lots of others. Mostly, water changes were done to clear the water environment the fish were in. Sometimes herbicide treatments or other things were done to combat bad tastes. Brett
Response:
>>see if there might be something with respect to southern >aquaculture out there. >This study was done in Alabama at Auburn University. >- Rod
No wonder. Those guys just think they know how to raise fish. Actually, I’ve many friends over there. They do some good work, but mostly in ecology and what they call "allied sceinces". Of course, 5300 pounds per acre is way under the industry average. Brett
Response:
This has certainly been very interesting. Did we reach a consensus for Wendy about frequent water changes? Small ponds, kept full, will have partial seasonal water changes due to overflow by rain, anyway. Are additional water changes helpful? I doubt there’s a concern about off-flavor in Koi, just about their growth and health. – Rod
Response:
> This has certainly been very interesting. Did we reach a consensus > for Wendy about frequent water changes? > Small ponds, kept full, will have partial seasonal water changes due > to overflow by rain, anyway. Are additional water changes helpful? > I doubt there’s a concern about off-flavor in Koi, just about their > growth and health.
I don’t think we did. Whereabouts do you live, Rod? I would think that most of North America inland from the ocean & east of the Rockies doesn’t get nearly enough rainfall to overflow the pond. I have had some overflow in the last few weeks, but before that I’ve been filling the pond to make up for evaporation all year long. It’s a very rare rainfall that arrives _after_ I’ve just topped up the pond. If I never topped it up, I wouldn’t be up to overflow level yet. So yes, additional water changes are helpful. I still don’t agree with you that we’d need to worry about alkilinity, etc, in a pond fed from a stream. You need the alkilinity to handle the pH in a stagnant pond. It’s much less necessary if you’ve got continual flow. But I’m not fond of the idea for a number of the other reasons expressed – possible toxins, inflowing eggs, etc, _outflowing_ eggs & fry. Spring fed ponds are nice, but then you still have the possibility of adding koi to your local stream (if you keep koi). You’re very right about the flavor – the Heron hasn’t complained once… — Derek (www.netcom.ca/~dbrought/pond) rec.ponds FAQ http://w3.one.net/~rzutt/faq.html One step above the ridiculous makes the sublime again. – Paine
Response:
>This has certainly been very interesting. Did we reach a consensus >for Wendy about frequent water changes? >Small ponds, kept full, will have partial seasonal water changes due >to overflow by rain, anyway. Are additional water changes helpful? >I doubt there’s a concern about off-flavor in Koi, just about their >growth and health. >- Rod
All the koi serious koi keepers I know make at least ten percent water changes daily, some a great deal more than that. Nitrates will build up in the typical "serious koi keeper’s" pond and have to be diluted. Also, the fish will use up a good bit of the minerals in the water, requiring either water change or addition of minerals. I don’t know an aquarist anywhere that doesn’t advocate regular water exchange. I’ve seen a few systems that seem to require less than others. A friend at UTMB (University of Texas Medical Branch) in Galveston has a nice setup for squids. His anearobic digestor takes care of nitrates for him. The aquarium cost about $130,000 to set up. Brett
Response:
– Hide quoted text — Show quoted text -> This has certainly been very interesting. Did we reach a >consensus > for Wendy about frequent water changes? > Small ponds, kept full, will have partial seasonal water >changes due > to overflow by rain, anyway. Are additional water changes >helpful? > I doubt there’s a concern about off-flavor in Koi, just about >their > growth and health. >I don’t think we did. >Whereabouts do you live, Rod? I would think that most of North >America inland from the ocean & east of the Rockies doesn’t get >nearly enough rainfall to overflow the pond. I have had some >overflow in the last few weeks, but before that I’ve been >filling the pond to make up for evaporation all year long. It’s >a very rare rainfall that arrives _after_ I’ve just topped up the >pond. If I never topped it up, I wouldn’t be up to overflow level >yet. So yes, additional water changes are helpful. >I still don’t agree with you that we’d need to worry about >alkilinity, etc, in a pond fed from a stream. You need the >alkilinity to handle the pH in a stagnant pond. It’s much less >necessary if you’ve got continual flow. But I’m not fond of the >idea for a number of the other reasons expressed – possible >toxins, inflowing eggs, etc, _outflowing_ eggs & fry. Spring fed >ponds are nice, but then you still have the possibility of adding >koi to your local stream (if you keep koi). >You’re very right about the flavor – the Heron hasn’t complained >once… >– >Derek (www.netcom.ca/~dbrought/pond) >rec.ponds FAQ http://w3.one.net/~rzutt/faq.html >One step above the ridiculous makes the sublime again. – Paine
The oldest known koi "Hanako" lived to be over 126 years old in a stream fed pond in Japan. In our area, rainfall and evaporation are nearly equal, however, they don’t come in equal amounts. If ponds are just "topped off" they get a buildup of salts. I recommend that water be removed, then added back to help prevent this. Brett
Response:
> In our area, rainfall and evaporation are nearly equal,
however, they don’t come in equal amounts. If ponds are just > "topped off" they get a buildup of salts. I recommend that
water be removed, then added back to help prevent this. I don’t actually ‘top up’, when I fill it I always overflow. I just went to the Environment Canada website to find out exactly what my average rainfall is. Typical government snafu – I can find 3 FAQs, all nearly identical, that pretend to answer the question "what is the average rainfall in <anytown>". None of them actually takes me to a place that can do that… — Derek (www.netcom.ca/~dbrought/pond) rec.ponds FAQ http://w3.one.net/~rzutt/faq.html There’s no more valour in you than in a wild duck! – Shakespeare
Response:
>Nitrates will build up in the typical "serious koi keeper’s" pond and >have to be diluted.
It could in an aquarium, not in a pond with a veggie filter and biofilter. The reason I posted the link to the study is that is has detailed water analyses that show that this just doesn’t happen. >Also, the fish will use up a good bit of the minerals in the water, >requiring either water change or addition of minerals.
What "minerals"? Fish absorb salt and oxygen through their gills; all other minerals have to come from their food. >I don’t know an aquarist anywhere that doesn’t advocate regular >water exchange.
A pond isn’t an aquarium. Pond gets much more light, and generally has much lower fish loading, than an aquarium. – Rod
Response:
>Whereabouts do you live, Rod? I would think that most of North >America inland from the ocean & east of the Rockies doesn’t get >nearly enough rainfall to overflow the pond.
This might help? Figure 3 "Lake Evaporation" in: http://geochange.er.usgs.gov/sw/changes/natural/et/ Broadly speaking, lake evaporation exceeds rainfall on an annual basis in the southwestern third of the US. For both Ontario (Derek) and Delaware (Rod), rainfall exceeds evaporation on an annual basis, our precipitation is pretty evenly spread through all 12 months, and our evaporation is nearly all in June-Sept. In an average year, our ponds would drop through summer, fill in fall, then overflow through May. More specific local lake evaporation data can be found on some state climatologist and regional USGS web pages. Also broadly speaking, it’s a heat balance. Evaporation (heat output) is dominated by the amount of sunlight falling on the pond (heat input), so most occurs in midsummer. If the pond is shaded, it’s annual evaporation will be less than that of an open lake. – Rod
Response:
>This has certainly been very interesting. Did we reach a consensus >for Wendy about frequent water changes? >Small ponds, kept full, will have partial seasonal water changes due >to overflow by rain, anyway. Are additional water changes helpful? >I doubt there’s a concern about off-flavor in Koi, just about their >growth and health. >- Rod
Definitely not any closer to a consensus. Unless we can somehow twist your arm, Rod? ;o) I have to be honest I did not read the published website, but am only going on information & experience from many hobbyists, local and on the net. That a pond left without water changes starts to have fish health problems in 3 to 5 years. Not doing water changes though could be because the person is not that involved with their pond and they not only don’t do water changes, they don’t clean out the muck, or screen for leaves or keep their filter up to speed (or have no filtration). Those that do water changes, usually do all the other stuff too. Me? Well, ya just can’t talk me out of water changes in the pond, but I have been known to let them go a little longer than a month in the fall. I’ve been doing them for 5 years and haven’t had a fish death due to water quality, so if it ain’t broke…… ;o) ~ jan
Response:
I just moved and now live next to a creek. I plan to build a new pond soon and I would like to use the water from the creek. I think I have thought the pros & cons through, but I am not sure. We are 20 feet above the creek, so no flooding. We have rights to the water, no problem there. Salmon come up the creek to spawn, so the water should be good? There are steelhead here also, so does that say the water is ok? The previous owner lowered a pump into the creek during the summer months and turned it on daily to water the flower beds & trees. I was thinking of tapping into that line and add fresh water everyday to the pond, allowing any extra to overflow somewhere/somehow. The new pond will be approx 3000 gallons, how much water would be too little or too much to add daily? Any advise/suggestions anyone can offer would be greatly appreciated. — -Wendy in CA
Response:
A friend of mine did almost the same thing, but feeds from a canal, then lets overflow run by "river" back to canal with mouth of river blocked by a wall of rocks to keep fish in. He uses a separate pump to run waterfall , with no filter, justs flushes pond daily from canal . His water is not crystal clear like a totally contained system with a bio-filter, but not too bad the 3 times I saw it – as clear as the water in the canal I guess at 3′ depth Gale – Hide quoted text — Show quoted text -> I just moved and now live next to a creek. I plan to build a new pond soon > and I would like to use the water from the creek. I think I have thought > the pros & cons through, but I am not sure. We are 20 feet above the creek, > so no flooding. We have rights to the water, no problem there. Salmon come > up the creek to spawn, so the water should be good? There are steelhead > here also, so does that say the water is ok? The previous owner lowered a > pump into the creek during the summer months and turned it on daily to water > the flower beds & trees. I was thinking of tapping into that line and add > fresh water everyday to the pond, allowing any extra to overflow > somewhere/somehow. The new pond will be approx 3000 gallons, how much water > would be too little or too much to add daily? Any advise/suggestions anyone > can offer would be greatly appreciated. > — > -Wendy in CA
Response:
It’s certainly fine to use good creek water to fill or top off the pond. But it might not be desirable to do daily water changes with it? It might be very low in alkalinity, hardness and plant nutrients, especially after rains when it might also be turbid. If it’s colder than the pond, it’ll slow down growth of both fish and plants. . The current trend in pond aquaculture is away from even annual water changes, to good biofiltration and reuse of the same water year after year. This study shows that water change results in no improvement in fish growth or productivity, it simply removes nutrients from the pond. http://ag.ansc.purdue.edu/aquanic/publicat/usda_rac/efs/srac/600fs.pdf My wife’s first pond is the same size as yours, and the first water change, just to clean out the bottom, was done after five years. – Rod
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> The current trend in pond aquaculture is away from even annual > water changes, to good biofiltration and reuse of the same water > year after year. This study shows that water change results in > no improvement in fish growth or productivity, it simply removes > nutrients from the pond.
http://ag.ansc.purdue.edu/aquanic/publicat/usda_rac/efs/srac/600f s.pdf But Rod, removal of nutrients is, for most of us, a Good Thing. Most of us aren’t doing aquaculture. I’d agree with you if it wasn’t for the fact that most of us have too _many_ nutrients, not too few. If you flush out all the unknowns, then you can take care of plants with addition of fertilizer and the fish with pellets. — Derek (www.netcom.ca/~dbrought/pond) rec.ponds FAQ http://w3.one.net/~rzutt/faq.html Those who make peaceful revolution impossible will make violent revolution inevitable – J.F. Kenn
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Thanks for the responses. They give me more to think about . I was planning on adding a just a few gallons, enough to top it off and spill out some. I was thinking on still having a veggie filter (100 gal Rubbermaid), gotta give the dragonflies a safe place to breed! The creek does get cloudy after a rain, but we have no rain here from April to October, the months I would be adding water. During the winter, if needed, I could top it off with well water? Ps, I am so excited about the thought of finally having frogs in the pond! — -Wendy in CA
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– Hide quoted text — Show quoted text ->It’s certainly fine to use good creek water to fill or top off the pond. >But it might not be desirable to do daily water changes with it? >It might be very low in alkalinity, hardness and plant nutrients, >especially after rains when it might also be turbid. If it’s colder >than the pond, it’ll slow down growth of both fish and plants. >.. >The current trend in pond aquaculture is away from even annual >water changes, to good biofiltration and reuse of the same water >year after year. This study shows that water change results in >no improvement in fish growth or productivity, it simply removes >nutrients from the pond. >http://ag.ansc.purdue.edu/aquanic/publicat/usda_rac/efs/srac/600fs.pdf >My wife’s first pond is the same size as yours, and the first water >change, just to clean out the bottom, was done after five years. >- Rod
Know your source water (to paraphrase what Rod’s got to say). I use mostly creek water, pump it up at about 350,000 gph. It is mostly good water. It goes to my reservoir of about 50 million gallons. I use reservoir water directly through my holding facility, one time through, then out. Rod is mostly right with respect to aquaculture water, in some systems. However, in sourthern ponds with extemely dense populations, especially catfish, tilapia, or striped bass, the water gets more than nutrients in it and has to be changed frequently. I worked for many years on a catfish farm where we did it a bit different. We did have biofiltration systems. Each system about 200 acres, with about 10 ponds, and two biofiltration ponds. Each fish pond changed out once in 9 days, each biofilter pond twice each day. Our "filters" were fish. We used several species, but some of the best were bighead carp (Aristichthyes nobilis), silver carp (Hypothalmichthyes nobilis), and paddlefish (Polyodon spathula). These fish actually filter the water for detritus and algae, through thier gills, converting nutrients into fish flesh while preparing the water to be returned to the catfish ponds. We achieved system wide production rates of over 25,000 pounds per acre when the industry average was about 3000 pounds per acre. Many similar type systems are in operation today. Just like a koi pond, except hundreds of acres and hundreds of millions of gallons. I’ve not been to the "aquanic" site in awhile, think I’ll go check it out. Got a lot of my fish living at Purdue (blue catfish). Never been there myself. Brett
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>But Rod, removal of nutrients is, for most of us, a Good Thing. >Most of us aren’t doing aquaculture. I’d agree with you if it >wasn’t for the fact that most of us have too _many_ nutrients, >not too few.
A pond with a balance of fish, plants and biofiltration won’t accumulate "too many nutrients". (In a desert, it might eventually accumulate too much hardness or salts. But most areas get enough rain that isn’t a problem.) Indeed, rivers and streams may have more nutrients than a balanced pond does. This is true of most rivers in my area: http://www-va.usgs.gov/chesbay/RIMP/ In a pond, we ideally want higher alkalinity and salinity than most water sources provide. Water changes remove these, and may add nutrients which trigger algae blooms. For example, after a rain, my local river goes down to pH 6.5, KH 10 mg/l, salinity ~0 ppm. In a dry spell, it rises to pH 7.6, KH ~50 mg/l, salinity >50 ppm. It’s flow and turbidity vary by a factor of ~100. Local streams vary even more than the river, by a factor of up to 1000 in flow and turbidity, with pH ~ 6 and KH ~ 0 during a rainstorm. In spring, they have an excess of phosphate which will trigger an algae bloom when warmed in a sunny pond. By late summer, phosphate is ~0.1 ppm in the river, but may remain high in shady streams that receive runoff. It’s constantly changing, but its alkalinity and salinity are always lower than we want in the pond. On the other hand, "Ponds may be operated for multiple years without draining with no decrease in fish production attributable to deterioration in environmental conditions within the pond." Conclusion on page 20 of: http://ag.ansc.purdue.edu/aquanic/publicat/usda_rac/efs/srac/600fs.pdf It isn’t clear that water changes are beneficial. – Rod
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I have no question about the engineering, but you have not addressed the problem of mixing wild and domestic water. You didn’t say what kind of fish you are looking to keep, but it is usually not a good idea to mix stuff, like plants, taken from the wild in with your fish. You may think the water — Todo — North Florida Koi Club, – Hide quoted text — Show quoted text -> I just moved and now live next to a creek. I plan to build a new pond soon > and I would like to use the water from the creek. I think I have thought > the pros & cons through, but I am not sure. We are 20 feet above the creek, > so no flooding. We have rights to the water, no problem there. Salmon come > up the creek to spawn, so the water should be good? There are steelhead > here also, so does that say the water is ok? The previous owner lowered a > pump into the creek during the summer months and turned it on daily to water > the flower beds & trees. I was thinking of tapping into that line and add > fresh water everyday to the pond, allowing any extra to overflow > somewhere/somehow. The new pond will be approx 3000 gallons, how much water > would be too little or too much to add daily? Any advise/suggestions anyone > can offer would be greatly appreciated. > — > -Wendy in CA
Response:
> I was thinking of tapping into that line and add >fresh water everyday to the pond, allowing any extra to overflow >somewhere/somehow. The new pond will be approx 3000 gallons, how much water >would be too little or too much to add daily?
We have a club member here with a 3500 gallon spring fed concrete lined koi pond. She would like the water to be more clear, but the addition of nutrients from the flowing water usually keep the water in stages of green. Regards, Hal
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- Hide quoted text — Show quoted text -> The current trend in pond aquaculture is away from even annual > water changes, to good biofiltration and reuse of the same >water year after year. This study shows that water change results in > no improvement in fish growth or productivity, it simply >removes nutrients from the pond. >http://ag.ansc.purdue.edu/aquanic/publicat/usda_rac/efs/srac/600f >s.pdf >But Rod, removal of nutrients is, for most of us, a Good Thing. >Most of us aren’t doing aquaculture. I’d agree with you if it >wasn’t for the fact that most of us have too _many_ nutrients, >not too few. If you flush out all the unknowns, then you can take >care of plants with addition of fertilizer and the fish with >pellets.
Not to mention lowering the bacteria and parasite levels. I wonder what the experts who write for KOI USA would say about the above publication? Concerning your wife’s pond, didn’t you say the area where you live receives a goodly amount of natural rain fall? If so, there’s your water change if that’s the case. Whereas those in the desert areas …… ;o) ~ jan
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– Hide quoted text — Show quoted text ->But Rod, removal of nutrients is, for most of us, a Good Thing. >Most of us aren’t doing aquaculture. I’d agree with you if it >wasn’t for the fact that most of us have too _many_ nutrients, >not too few. >A pond with a balance of fish, plants and biofiltration won’t >accumulate "too many nutrients". >(In a desert, it might eventually accumulate too much hardness >or salts. But most areas get enough rain that isn’t a problem.) >Indeed, rivers and streams may have more nutrients than a >balanced pond does. This is true of most rivers in my area: >http://www-va.usgs.gov/chesbay/RIMP/ >In a pond, we ideally want higher alkalinity and salinity than most >water sources provide. Water changes remove these, and may >add nutrients which trigger algae blooms. >For example, after a rain, my local river goes down to pH 6.5, >KH 10 mg/l, salinity ~0 ppm. In a dry spell, it rises to pH 7.6, >KH ~50 mg/l, salinity >50 ppm. It’s flow and turbidity vary by >a factor of ~100. Local streams vary even more than the river, >by a factor of up to 1000 in flow and turbidity, with pH ~ 6 and >KH ~ 0 during a rainstorm. >In spring, they have an excess of phosphate which will trigger >an algae bloom when warmed in a sunny pond. >By late summer, phosphate is ~0.1 ppm in the river, but may >remain high in shady streams that receive runoff. >It’s constantly changing, but its alkalinity and salinity are always >lower than we want in the pond. >On the other hand, "Ponds may be operated for multiple years >without draining with no decrease in fish production attributable to >deterioration in environmental conditions within the pond." >Conclusion on page 20 of: >http://ag.ansc.purdue.edu/aquanic/publicat/usda_rac/efs/srac/600fs.pdf >It isn’t clear that water changes are beneficial. >- Rod
Those guys are not raising many fish in those ponds. Sure, with a standing crop of less than 1500 pounds per care, the pond can be in production for a long while. With the amounts of biomass in southern ponds (nowadays upwards of 10,000 pounds per acre) the pond must be drained, dried, bulldozed, limed, and refilled with fresh water at least once every four or five years. I do my ponds twice a year, at least. Also of extreme import to the pond’s usefulness in aquaculture is its ability to provide fish that "taste good". If the pond is not in good condition, it will show up in the flavor of the fish produced in it. This is of much greater economic importance than actual ability to produce fish flesh. If they don’t pass muster in the taster’s kitchen, they don’t get harvested, processed, and sold. Consider the loss in raising a bunch of fish you can’t sell because they taste bad. "off flavor" is the biggest problem facing modern aquaculturists today, more than disease, more than bad water quality, more than labor problems, etc. Not having the time to do it myself, see if there might be something with respect to southern aquaculture out there. The "Guru" of warmwater fish ponds is Dr. Claude Boyd. His book "Water Quality in Warmwater Fish Ponds" is the "Bible" of water quality in the South. He’ll be the first to tell you that you can indeed "wear the wet" out of fish pond water. Brett
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>I have no question about the engineering, but you have not addressed the >problem of mixing wild and domestic water. You didn’t say what kind of fish >you are looking to keep, but it is usually not a good idea to mix stuff, >like plants, taken from the wild in with your fish. You may think the water
Of even greater concern is the possibility of pathogens. To keep out unwanted fish, I filter my "live water" through a 100 micron sock as I impound it into fish ponds. This keeps out unwanted fish and eggs. When I worked on the big catfish farm, we used water from the Brazos River to fill ponds. We raised lots of fish in that water. I still do at my "real job" at the bass fishing resort. We impound river water at the rate of 80,000 gph for 300 acres of fishing lakes and 15 acres of hatchery ponds. Of late, we had to stop taking river water due to high salinity (over 15 ppt or half seawater strenght). When I called the river authority to complain (we pay for that water), they told me to "check my contract", they only gaurantee "quantity". Makes me wonder what folks around there are drinking. Brett – Hide quoted text — Show quoted text ->– >Todo — North Florida Koi Club, > I just moved and now live next to a creek. I plan to build a new pond >soon > and I would like to use the water from the creek. I think I have thought > the pros & cons through, but I am not sure. We are 20 feet above the >creek, > so no flooding. We have rights to the water, no problem there. Salmon >come > up the creek to spawn, so the water should be good? There are steelhead > here also, so does that say the water is ok? The previous owner lowered a > pump into the creek during the summer months and turned it on daily to >water > the flower beds & trees. I was thinking of tapping into that line and add > fresh water everyday to the pond, allowing any extra to overflow > somewhere/somehow. The new pond will be approx 3000 gallons, how much >water > would be too little or too much to add daily? Any advise/suggestions >anyone > can offer would be greatly appreciated. > — > -Wendy in CA
Response:
>Those guys are not raising many fish in those ponds. Sure, with a standing >crop of less than 1500 pounds per care, the pond >can be in production for a long while. With the amounts of biomass in >southern ponds (nowadays upwards of 10,000 pounds per >acre) the pond must be drained, dried, bulldozed, limed, and refilled with >fresh water at least once every four or five >years. I do my ponds twice a year, at least.
They were producing about 6000 kg/ha (5300 lbs/acre) of 1 pound channel catfish. See Table 6 on page 19: http://ag.ansc.purdue.edu/aquanic/publicat/usda_rac/efs/srac/600fs.pdf Their levee ponds had an average depth 3 feet, so that’s an annual production of 1 lb/200 gallons, which is higher than a typical garden pond. (Of course, carp aren’t catfish!) – Rod
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>see if there might be something with respect to southern >aquaculture out there.
This study was done in Alabama at Auburn University. – Rod
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>Concerning your wife’s pond, didn’t you say the area where you live >receives a goodly amount of natural rain fall? If so, there’s your water >change if that’s the case. Whereas those in the desert areas ……
On average, we get 41 inches, pretty evenly though all 12 months. Average depth is 4 feet. The pond does overflow in winter and spring, so rain probably does exchange about 1/3 of it’s volume per year. The study I mentioned also tried lowering the pond, so rain did not cause overflow. Again, no change in water quality, no loss in growth or productivity, after 3 years. But most of us wouldn’t want to let our garden pond get a foot low by the end of summer. In our second pond, I lined the sides so it can drop 6" without exposing the liner. That helps! – Rod
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– Hide quoted text — Show quoted text ->Those guys are not raising many fish in those ponds. Sure, with a standing >crop of less than 1500 pounds per care, the pond >can be in production for a long while. With the amounts of biomass in >southern ponds (nowadays upwards of 10,000 pounds per >acre) the pond must be drained, dried, bulldozed, limed, and refilled with >fresh water at least once every four or five >years. I do my ponds twice a year, at least. >They were producing about 6000 kg/ha (5300 lbs/acre) of 1 pound >channel catfish. See Table 6 on page 19: >http://ag.ansc.purdue.edu/aquanic/publicat/usda_rac/efs/srac/600fs.pdf >Their levee ponds had an average depth 3 feet, so that’s an annual >production of 1 lb/200 gallons, which is higher than a typical garden >pond. (Of course, carp aren’t catfish!) >- Rod
Did they say how they tasted? In densely stocked catfish ponds with little or no water exchange, the catfish get what the tasters call "sewage off flavor", one of the worst. Our taster could discern over 100 distinct off flavors. She taught me a great deal about the subject. Each morning after the samples had been brought to the taste kitchen I’d show up for the data sheet and for breakfast. She would keep the "good samples" for me which I put a bit of lemon pepper and salt on, then ate. The sampler would catch the fish from the pond to be sampled, usually two or three, cut the tail off at the vent, put in a baggy with a lable, then bring it to the kitchen. The taster would put the sample in a brown paper lunch bag and microwave (with no seasonings) for 6 minutes. She (tasters I knew were all female, don’t know why) would break open the bag and sniff, if it smelled bad, she marked it failed and threw it away. If it smelled OK, she would put some in her mouth, chew it a bit, and spit it out. If it passed, it was marked on the sheet. If it failed, it was ranked as how bad and why on the data sheet. I learned that the fish taste was a continuum, not a "good or bad" type thing. Some off flavors were easier to contend with than others. Some only required three or four days of "depuration" in a freshwater holding tank. Others took months to get rid off. In almost every case, a water change was prescribed. Some of the more common off flavors we had and why: Sewage-bad water muddy/musty-blue green algea bloom woody-tannic acid diesel-fuel spill cardboard-brown or red algae bloom soil or dirt-green algae bloom chemical-chemical spill, caught too soon after therapuetic treament lots of others. Mostly, water changes were done to clear the water environment the fish were in. Sometimes herbicide treatments or other things were done to combat bad tastes. Brett
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>>see if there might be something with respect to southern >aquaculture out there. >This study was done in Alabama at Auburn University. >- Rod
No wonder. Those guys just think they know how to raise fish. Actually, I’ve many friends over there. They do some good work, but mostly in ecology and what they call "allied sceinces". Of course, 5300 pounds per acre is way under the industry average. Brett
Response:
This has certainly been very interesting. Did we reach a consensus for Wendy about frequent water changes? Small ponds, kept full, will have partial seasonal water changes due to overflow by rain, anyway. Are additional water changes helpful? I doubt there’s a concern about off-flavor in Koi, just about their growth and health. – Rod
Response:
> This has certainly been very interesting. Did we reach a consensus > for Wendy about frequent water changes? > Small ponds, kept full, will have partial seasonal water changes due > to overflow by rain, anyway. Are additional water changes helpful? > I doubt there’s a concern about off-flavor in Koi, just about their > growth and health.
I don’t think we did. Whereabouts do you live, Rod? I would think that most of North America inland from the ocean & east of the Rockies doesn’t get nearly enough rainfall to overflow the pond. I have had some overflow in the last few weeks, but before that I’ve been filling the pond to make up for evaporation all year long. It’s a very rare rainfall that arrives _after_ I’ve just topped up the pond. If I never topped it up, I wouldn’t be up to overflow level yet. So yes, additional water changes are helpful. I still don’t agree with you that we’d need to worry about alkilinity, etc, in a pond fed from a stream. You need the alkilinity to handle the pH in a stagnant pond. It’s much less necessary if you’ve got continual flow. But I’m not fond of the idea for a number of the other reasons expressed – possible toxins, inflowing eggs, etc, _outflowing_ eggs & fry. Spring fed ponds are nice, but then you still have the possibility of adding koi to your local stream (if you keep koi). You’re very right about the flavor – the Heron hasn’t complained once… — Derek (www.netcom.ca/~dbrought/pond) rec.ponds FAQ http://w3.one.net/~rzutt/faq.html One step above the ridiculous makes the sublime again. – Paine
Response:
>This has certainly been very interesting. Did we reach a consensus >for Wendy about frequent water changes? >Small ponds, kept full, will have partial seasonal water changes due >to overflow by rain, anyway. Are additional water changes helpful? >I doubt there’s a concern about off-flavor in Koi, just about their >growth and health. >- Rod
All the koi serious koi keepers I know make at least ten percent water changes daily, some a great deal more than that. Nitrates will build up in the typical "serious koi keeper’s" pond and have to be diluted. Also, the fish will use up a good bit of the minerals in the water, requiring either water change or addition of minerals. I don’t know an aquarist anywhere that doesn’t advocate regular water exchange. I’ve seen a few systems that seem to require less than others. A friend at UTMB (University of Texas Medical Branch) in Galveston has a nice setup for squids. His anearobic digestor takes care of nitrates for him. The aquarium cost about $130,000 to set up. Brett
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– Hide quoted text — Show quoted text -> This has certainly been very interesting. Did we reach a >consensus > for Wendy about frequent water changes? > Small ponds, kept full, will have partial seasonal water >changes due > to overflow by rain, anyway. Are additional water changes >helpful? > I doubt there’s a concern about off-flavor in Koi, just about >their > growth and health. >I don’t think we did. >Whereabouts do you live, Rod? I would think that most of North >America inland from the ocean & east of the Rockies doesn’t get >nearly enough rainfall to overflow the pond. I have had some >overflow in the last few weeks, but before that I’ve been >filling the pond to make up for evaporation all year long. It’s >a very rare rainfall that arrives _after_ I’ve just topped up the >pond. If I never topped it up, I wouldn’t be up to overflow level >yet. So yes, additional water changes are helpful. >I still don’t agree with you that we’d need to worry about >alkilinity, etc, in a pond fed from a stream. You need the >alkilinity to handle the pH in a stagnant pond. It’s much less >necessary if you’ve got continual flow. But I’m not fond of the >idea for a number of the other reasons expressed – possible >toxins, inflowing eggs, etc, _outflowing_ eggs & fry. Spring fed >ponds are nice, but then you still have the possibility of adding >koi to your local stream (if you keep koi). >You’re very right about the flavor – the Heron hasn’t complained >once… >– >Derek (www.netcom.ca/~dbrought/pond) >rec.ponds FAQ http://w3.one.net/~rzutt/faq.html >One step above the ridiculous makes the sublime again. – Paine
The oldest known koi "Hanako" lived to be over 126 years old in a stream fed pond in Japan. In our area, rainfall and evaporation are nearly equal, however, they don’t come in equal amounts. If ponds are just "topped off" they get a buildup of salts. I recommend that water be removed, then added back to help prevent this. Brett
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> In our area, rainfall and evaporation are nearly equal,
however, they don’t come in equal amounts. If ponds are just > "topped off" they get a buildup of salts. I recommend that
water be removed, then added back to help prevent this. I don’t actually ‘top up’, when I fill it I always overflow. I just went to the Environment Canada website to find out exactly what my average rainfall is. Typical government snafu – I can find 3 FAQs, all nearly identical, that pretend to answer the question "what is the average rainfall in <anytown>". None of them actually takes me to a place that can do that… — Derek (www.netcom.ca/~dbrought/pond) rec.ponds FAQ http://w3.one.net/~rzutt/faq.html There’s no more valour in you than in a wild duck! – Shakespeare
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>Nitrates will build up in the typical "serious koi keeper’s" pond and >have to be diluted.
It could in an aquarium, not in a pond with a veggie filter and biofilter. The reason I posted the link to the study is that is has detailed water analyses that show that this just doesn’t happen. >Also, the fish will use up a good bit of the minerals in the water, >requiring either water change or addition of minerals.
What "minerals"? Fish absorb salt and oxygen through their gills; all other minerals have to come from their food. >I don’t know an aquarist anywhere that doesn’t advocate regular >water exchange.
A pond isn’t an aquarium. Pond gets much more light, and generally has much lower fish loading, than an aquarium. – Rod
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>Whereabouts do you live, Rod? I would think that most of North >America inland from the ocean & east of the Rockies doesn’t get >nearly enough rainfall to overflow the pond.
This might help? Figure 3 "Lake Evaporation" in: http://geochange.er.usgs.gov/sw/changes/natural/et/ Broadly speaking, lake evaporation exceeds rainfall on an annual basis in the southwestern third of the US. For both Ontario (Derek) and Delaware (Rod), rainfall exceeds evaporation on an annual basis, our precipitation is pretty evenly spread through all 12 months, and our evaporation is nearly all in June-Sept. In an average year, our ponds would drop through summer, fill in fall, then overflow through May. More specific local lake evaporation data can be found on some state climatologist and regional USGS web pages. Also broadly speaking, it’s a heat balance. Evaporation (heat output) is dominated by the amount of sunlight falling on the pond (heat input), so most occurs in midsummer. If the pond is shaded, it’s annual evaporation will be less than that of an open lake. – Rod
Response:
>This has certainly been very interesting. Did we reach a consensus >for Wendy about frequent water changes? >Small ponds, kept full, will have partial seasonal water changes due >to overflow by rain, anyway. Are additional water changes helpful? >I doubt there’s a concern about off-flavor in Koi, just about their >growth and health. >- Rod
Definitely not any closer to a consensus. Unless we can somehow twist your arm, Rod? ;o) I have to be honest I did not read the published website, but am only going on information & experience from many hobbyists, local and on the net. That a pond left without water changes starts to have fish health problems in 3 to 5 years. Not doing water changes though could be because the person is not that involved with their pond and they not only don’t do water changes, they don’t clean out the muck, or screen for leaves or keep their filter up to speed (or have no filtration). Those that do water changes, usually do all the other stuff too. Me? Well, ya just can’t talk me out of water changes in the pond, but I have been known to let them go a little longer than a month in the fall. I’ve been doing them for 5 years and haven’t had a fish death due to water quality, so if it ain’t broke…… ;o) ~ jan
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