Pond Boss Forums INTRO Questions & Observations Would this help cool my pond?

If you read my other thread you know I've successfully held trout over the summer in my pond the last 2 years. This summer I had to be pushing the limits with my pond temps, and I want to try a few things to help counter that. While I was successful this year, my trout HAD to be stressing.

The first thing I was thinking of doing was moving the aeration compressor for my pond to my basement. My pond is close to my house and currently it's under my deck where the temps have to be high from the sun beating down on the deck mid day. My logic with moving it to the basement is I would be pumping much cooler (65-70 deg?) air during the hot days.

The second thing I was thinking of doing is adding well water. My pond is a water table pond and has a sandy bottom. Would it benefit me to hand drive a 1 1/4" well about 20 feet down and pump that water in my pond for the month or 2 when my temps would be the highest? I was thinking about driving it right in the pond where it's about 2 feet deep, and letting the water fall right in to the pond. My pond is about 1/5 acre and around 10 feet deep at the deepest, but most of it is around 6 feet deep. How much water would I have to pump, and should I do something to it to add DO before it goes in the pond?

Well water is your best bet, I think. But I've heard that well water is devoid of O2, so you are correct in that you have to 'treat' the water.

Splashing the water over several obstacles on it's downward path to the pond works, but there is a trade off to the well water getting warmer along the way as it splashes down and mixes with the air.

You have to add the O2 to the water, though.

Moving the pump to cooler temps wont change the compressed air temp any, it will exhaust off the same. The motor windings might be a few degrees cooler but depending on the style of compressor is probably oil less and made to run constantly and in hot temps.Sunil is correct on the well water.

Wow, I would have thought putting the pump in a cooler enviroment would pump cooler air. Good thing I asked!

Anyone have any input as to how much well water I'd need to pump to impact the pond temp?

To calculate what you would need, we would need to know how many GPM your potential well would produce, and then the amount of water in your pond.

They would be rough numbers, and not firm.

Not sure if my methodology is technically correct, but logic suggests that 10k gal of 68F water added to 1-ac/ft (325,800 gal) of 85F water will produce a combined temperature of 84.5F (a .5 degree reduction to the larger water-volume).

Four variables impact the final value, and assumes instantaneous blending of both volumes and their relative temps. Plus, the initial change may be short-lived due to the ambient air-temp and other variables that affect heat induction or dissipation.

325,800 x .0085 = 2,769
10,000 x .0068 = 68
Total of the two volumes: 335,800 gal
Total thermal units: 2,837

2,837
335,800 = .00845 (= 84.5F)

I would agree with using aerated well water to get your trout pond to a less stressful temp., this is just a WAG but from my experience with supplying my pond with stream water I think about 5 GPM of cold well water to your small pond could make a reasonable difference, and split the flow to the pond with a separation of at least 30 ft. to allow a larger area of cooler water.

It's really something you would have to experiment with.

I suspect Cecil would have some very helpful knowledge to share on this subject... Too bad he's not participating anymore!

It's all academic until you know the well production (as Sunil states above).

What would be the limiting factor on the amount of water my well could deliver? It doesn't seem like the amount of water I tap in to would be an issue. If I dig a 3 foot deep hole anywhere around my property (except the hill my house is built on) it fills with water.

Limiting factors are
1) soil capacity to move water without making a channel to soil that doesn't hold water and sucking air
2) well screen capacity. (I ran a double screen on my well so that wasn't a limiting factor)
3) amount of water your pump can push, when figuring in the head pressure and pipe size/length of run for any restrictions.
4) depth of your pocketbook to afford a large enough well, pump and electricity needed to keep it running.

I'd look at it a different way. I wouldn't use a bottom diffuser, I'd WANT to set up a thermocline in the pond with the well water, and make sure that it was saturated with O2 before it ever hit the pond. The trout can live below the thermocline provided they have plent of O2. They can dash up for food, or you can feed them sinking food.

I like this idea. Are there any good plans to make, or places to buy something to add O2 to well water?

Some other options to help cool your pond would be to place your diffuser in shallow water and hook your air pump to a thermostat so that it runs only when air temp. is below water temp., also a surface fountain running during cooler night temps., and some artificial islands which will add shade and other benefits to the pond.

There's a guy in Illinois who is running O2 to the water that's under the thermocline in his deep lake and getting trout to live year round.

I think that if you could bounce the water over some rocks in a shaded area, then put it in the pond, it might do the trick. Well water uptakes O2 rapidly.

Some years back, Mother Earth News (?) did an article on how to air-condition your off-grid home by pumping air through 6" burried tubes 8' or more in the ground, as differential in the dirt temps that deep is significant in the heat of summer. The same physics would apply if you pumped your pond water through a series of tubes under-ground, though personally I would use hundreds of feet of coiled 1/2" poly in lieu of the bigger stuff they suggested for home-made air-conditioning. Desparate times take desparate measures...

It's called geo-thermal. Some guys here have done it in the ponds.

Still looking for a good system for adding oxygen to well water. I'm drawing up plans, but it seems like a simple system would be available(I think I'm over thinking it).

Also, if I drove and ran the pump over a few feet of water, what kind of special line would I need to run the electricity underwater?

How about a packed column made of five gallon buckets connected in a series hung from a u post over your well? You pump the water up a few feet to the top bucket and it drops through via gravity through each bucket packed with plastic media.

That's what I do for my trout pond and what many trout farms and even state and federal facilities that raise trout do. Not only are you aerating the well water you are blowing off nitrogen gas, carbon dioxide, and hydrogen sulfide gas which are bad for your fish.

The buckets have cutouts in the bottom that with a shelf left are lined with plastic screening (as used in fish cages) to keep the media in and allow water to drop through. The very top bucket has a plastic piece with holes in it to distribute the water evenly.

D.O. saturation goes from almost nil to 90 percent by the time the water hits the pond.

Here are some pictures. Notice the iron in the water has discolored everything.





Top bucket of the series.



Different view of top bucket.



Again different view.





Plastic media:






My well water is introduced from a 6 by 6 pit after the packed column (not necessary for one pond as I use it to divert water via gate valves to the pond of my choosing), and then underground via a 4 inch PVC pipe to the trout pond. At the trout pond it's introduced at the surface with an upturned elbow to get further aeration.

The idea of introducing aerated well water to the bottom of a pond makes sense but I've never tried it.


How large is this pond again and what is the average and maximum depth?

A few trout from my trout pond:

What if you pump your well water into a tray. The tray is connected to a pipe or 2 to spread out your cool water like AP suggested. The pipe runs to the deepest part of your pond and gravity takes it from the tray to the bottom of your pond.

As far as what to build in the tray to add oxygen. Like Esshup said cold well water takes up O2 rapidly. Spaying it on rocks or over a couple of small paddle wheels would add alot I would guess.

I have tested my kitchen sink and its between 8-9 ppm with the little oxygenator deal standard on every tap. never checked it with it off to see how much it adds.

K I just tested DO2 out of tap
1: oxygenator off tap. caught right at tap= 2ppm
2:oxygenator on caught right at tap= 4ppm
3:oxygenator on with 3 inches of water
with tap on fill sample from bottom of sink= 7.5ppm