Pond Boss Forums AERATION Systems questions Aerating well water

I believe Cecil Baird aerates well water prior to release to his ponds. I think I want to do the same. Below is my rationale and situation. Hopefully some of the folks can validate and suggest a design.

I have a hard time with my trout over the summer because of rising water temps. Quarter acre pond, 9 feet deep. The 1/3 hp compressor aerates through membrane diffusers on the bottom. But of course this turns over the water column - so in July, August the whole pond gets to low to mid 70s F. So it's a tough situation. The high temps have little capacity to hold dissolved O2. But without the aeration, I end up with thermal layering and low DO anyway.

I'm thinking of digging a shallow non-culinary well looking for about 25-35 gpm for summer use. Water temps from the well would be about 45 deg f. I realize that is not a lot of flow, but hopefully would be enough to make a difference.

If I aerated before releasing it to the pond, I hope to have an oxygenated lower layer of cool water. I'd turn off the bottom membrane diffusers. And just oxygenate the cool well water. The bottom would be cool with good dissolved oxygen - hopefully. The top could warm up without much impact on trout health.

Is this what any obsessive-compulsive PBer would do? ...Someone with more dollars than sense?

Mason,

Try running your diffusers only at night in the summer vs. all day. Diffusers off of an air compressor are really not aerators at all. They are mixers. Very poor for actually adding oxygen to the water. I think running them 12 hours a day would be sufficient and any plants or phytoplankton you have in the pond should produce oxygen during the day anyway.

As far as well flow into the pond, that will definitely reduce the water temperature if there is enough. The question is, is 25 to 35 gpm enough to do so in a 1/4 acre pond? My pond is only 1/10 acre and even though I pump in 45 gpm 24/7, I still get up to 65 on the surface in really hot weather. It's possible it's cooler down deeper, but I've never been able to get out far enough to do a temp profile without a pier or boat on the pond.

That said, your ground water is cooler than mine at 45 F. vs. my ground water of 51.6. F. That will adding some cooling power, but how much is the question. And if you have any shade at all, you have another advantage over me.

As far as aerating the ground water before entering the pond, the more saturation you get the better you will be off. However I'm not sure if you need to go as far as using a packed column like I do. Maybe cascading it over some rocks would suffice?

I often wonder if one could achieve close to 100 percent oxygen saturation in the well water, and then flow the water directly to the pond bottom (Pipe enters the pond on the bottom vs. being dropped in at the top), if that would sustain a cold water layer that has enough oxygen for the fish? Of course you'd have to forego the diffusers if you wanted to go that route. I've never tried it though. It seems the cold water would be dense enough vs. the warmer water around and above it to stay down.

I would also suggest you make your overflow to skim warmer water off of the surface vs. the cooler deeper water.

Thanks, Cecil. I'll look forward to your response, when you get time.

I actually have been running the diffusers at night during the summer. I have them on an electronic timer. But the bottom water temps still climb to the mid 70s.

Oh I see. Then you definitely need well flow to cool things down. The question is how much do you need? And can you get by by feeding it into the bottom of your pond without the use of diffusers instead of trying to cool down the entire water column?

The only other alternative is to dig a smaller pond upstream for your trout that is easier to cool and make your present pond a "coolwater pond" that receives flow from the trout pond with smallmouth or all female yellow perch or something like that.

Personally if it was me I'd go the latter route. Lots cheaper than trying to pump up lots of ground water unless you have a high static well water level. If that were the case you could use a surface pump to get a good flow out with much less power than a submersible well pump.

Another consideration may be to extend the diffuser up to the 4 ft area with a simple riser. If for example you have a diffuser that lifts 2300 gpm at 1 cfm at a 9 ft depth simply raising it to 4 ft below the surface would slow it down to 1400 gpm. I would keep it in the same location just raise it and as Cecil states run it at night only. Keep in mind even at 68F at 80% saturation (sea level) you can still maintain 7.27 ppm DO.Pull the overflow water off of the top and continue adding well water. Some DO will diffuse into the bottom water and should give you a desired temp and DO haven to get through the tough summer months.In this case some stratification is desired.Depending on the type of pump and cfm output it may be necessary to vent off some of the excessive air output in the summer months also.Some 1/3 hp pumps supply from 1.5 to 4.4 cfm open flow.This is a situation that you should know the exact specs on your compressor and more importantly the diffuser.

Ted,

His compressor seems a bit overpowered for a 1/4th acre pond too isn't it? I use a 1/3 hp. rotary in my .62 acre pond and it's plenty. I've even run four airlines and diffusers from it.

Another suggestion from up north...
Often the only species raised in our neck of the woods are trout.
Raising trout in small dugouts or shallow ponds can be tricky.

Aerating on a timer just at night is a solution, but even that fails when night time temperature is warm... we do get heat waves in the summer!

What I found works best, instead of the regular timer is to use the Kasco Marine Temperature Control device like the C-10
http://www.de-icer.com/products_c10.htm It is marketed as a tool that allows your deicer to start when freezing temperatures are reached, in fact you can set it much higher to say 67 F or 22 C and you will never have aeration going on above that temperature.

It allows to aerate only when temperature is bellow a certain threshold, so some nights you wont have aeration, but other days, you could aerate while a cold front passes by.

That way, we can keep aerating disks or bubble tubing at the bottom of the pond and circulate water without adding extra heat to the pond. In fact, we even have measured lowering temperatures of up to 2 Celsius (about 5 F)in 24 hours.

Works for us who raise trouts in shallow ponds and are typically not successful.

Aerating a well sounds ok too! ... my two cents!

Cecil, yes 1/3 hp can be a lot but I have seen cfm's as low as 1.5 with them.Most 1/3 hp rotary vanes and pistons are 4-5 cfm today.The Gast 0523 1/4 hp has 4.2 cfm open flow so these are powerful little pumps. NE Mason could probably get by with a small linear pump with the raised diffuser.The problem with the temp timers is you could go days in the summer without aeration and in a 1/4 acre pond run low on DO quickly.Perhaps a combination of timer, raised diffuser, (DO meter would be great also) Also with a 1/4 acre pond any type of aeration is going to warm the entire water column to some degree.Small ponds and trout are always a challange in the warm months.At times I wonder if all trout ponds are meant for trout year in and year out.

Yes small ponds can be negative for trout survival but so can large ones. Obviously bigger is not better if you are running in well water to cool the water down. With a smaller pond you don't have to run in as much well water. My trout ponds are steep sided and quite deep for the surface area which goes a long way to making it difficult for the sun to warm them in summer. Of course I also run in aerated well water 24/7 six to seven months of the year.

You could try adding water to the bottom to create a safe zone for the trout and aerate the well water using a Venturi Fitting and an oxygen cone.

I am going to experiment with this setup over the summer. I plan on pumping during the day through the summer and running the aerator when air temps drop below 70. Found a thermostat on ebay at a good price that should do the job.

Try this link for a good discussion wrt trout.

http://www.pondboss.com/forums/ubbthreads.php?ubb=showflat&Number=78263&fpart=1

Limnology and ecology are not always going to be as intuitive as one might think. Plus, feeding fish during hot weather is not a great idea with trout.

NE
Here's one of my screwball ideas which i might try if we get a real hot summer, I know your gonna laugh. Take 10 or 20 sheets of 1 inch styrofoam insulation with the aluminized facing, link them together with rope at both ends,and put them out in the morning on sunny days,and bring them in at night. They can be stacked next to the pond, and put out ,and brought in without too much trouble. It's sort of a last ditch idea to keep temps down.
NO I don't drink!!!

ap, that might keep the water a little cooler but covering the surface will interfere with the water taking on oxygen.