Aerator and bottom heater?

[waynefrcan]

My local pond expert recommends a bottom heater and a bottom aerator. Where the aerator sits 1 ft higher then the heater. Something about the aerator drawing geothermal heat energy from the earth? This combo should keep a hole open in the ice. If it does ice over the aeration, a gas exchange will still occur. The heater is to keep the bottom water warmer. Is all this Star Trek or what?

We are frozen solid for 4-6 months a year.

 

[Craig58]

Interesting concept. I'm not sure I agree with it though. But for your area it might be right.

In winter you get an inversion. That is the water at the top of the pond is colder than the water at the bottom. In the summer, the reverse is true. Wamer on top and colder on bottom.

Ice is a good insulator. The thicker the ice, the more insulation from the exterior elements.

The idea I've been taught is that you want the bubbler and heater close to the surface so as to disturb the bottom layers as little as possible. Oxygen levels aren't the concern as much in the winter as is a means for decomposition and respiratory gases to escape. If you have a pretty clean pond bottom, with little debris, and you don't have an overcrowding fish population, the pond can go a couple of weeks or longer without hole.

The problem with a bottom aerator is that as the bubbles rise, they pull water up with them. As the water is pulled up, other water needs to replace it. This usually causes water to be drawn down the side walls of the pond to the area below the aerator. Of course it depends on the shape of the pond, the strength of the aerator, the depth of the pond, the depth of the aerator, etc.

But this pulls the coldest water from the top, (possibly 33F/1C), and pulls it to the bottom and than back up the bubble column. This than makes the water on the bottom colder than it should be. I'm going to run some experiments this winter in my new pond since it doesn't have any fish in it and see if I can see some difference between having the aerator on the bottom or on the surface and how much of a difference.

But with a bottom heater, that might counteract the mixing I don't know. The earth will have a certain amount of heat but will it be enough to take advantage of in the pond? I don't know.

You'll have to let us know how it works. But I would ask the seller, if the company that designed it, has any studies on how it works and what the temperature differences were in their test pond. Can they explain any of the science behind it?

For cold weather testing you folks have a lot tougher test conditions than I'll ever have!!!

Craig

 

[waynefrcan]

But if you believe the studies done [links in "location of circulation pump" topic] then our ponds at 2-5 ft do not have a temp difference anywhere. Probably all constant at 3 C or 35 F which is too cold for the fish.

Yes also In the past I have just used a surface pump to bubble over the water and a floating heater. Seems to be the most used method.

Yes do some tests for us this winter. Mucky is doing some as well. Neither of you have as cold winters as me, but still i want to know the results.

 

[Craig58]

Wayne,

The Ohio articles were primarily about natural ponds done by the Ag extension agents. These are ponds where wind conditions probably play a much bigger role than in our backyard ponds. Yours has a six foot fence around it for instant. The amount of wave creation on a body of water is directly related to the distance the wind is in contact with the surface. One of the reasons large lakes can have some good size waves that can swamp a canoe. There is actually a formula for predicating wave height by wind speed and open lake surface area.

For most of our sheltered backyard ponds wind isn't going to play much of a role. So I do believe that the ponds stratify. Also, the articles mentions 39F as the inversion point. That is not the warmest the water can stratify to on the bottom of a pond. It is the temperature that causes the pond to "flip" with colder water rising to the top and warmer water going to the bottom.

It seems several people in that posting were taking that to mean that the fish would all be subjected to 39F water at least and the whole pond would be 39F. From what I've read before, pond bottoms can remain as warm as 45-49F on the bottom if they stratify. I'll test that this winter to find out. Its the only way I'll know for sure.

Craig

 

[Dave 54]

The heat from the earth concept does work but you need to go down under the pond by about 6 ft then lay underfloor heating tubing conected to a central heating pump and pipe the heat around the pond,
One that a friend is actively thinking about is to use the same concept but use a large compost heap for the heat temperatures can reach an inpressive 42.c in the middle of a large heap .
However it is firmly still on the drawing board at this time we'll see if it ever comes to fruition.

rgrds

Dave

 

[Dave 54]

But if you believe the studies done [links in "location of circulation pump" topic] then our ponds at 2-5 ft do not have a temp difference anywhere. Probably all constant at 3 C or 35 F which is too cold for the fish.

Yes also In the past I have just used a surface pump to bubble over the water and a floating heater. Seems to be the most used method.

Yes do some tests for us this winter. Mucky is doing some as well. Neither of you have as cold winters as me, but still i want to know the results.

If you are like we Brits who actively do water changes throughout the winter we use a trick that is to trickle the water slowly back in doing it this way during a winter water change the pond has the effect of warming the trickling water to near as damn it the pond temperature you loose around .5 of a degree, however the only drawback with this is a 30% waterchange takes forever to do.
The pond itself being covered in Polycarbonate sheets to keep the water some degrees above that of the outside temperature

rgrds

Dave

 

[sissy]

The heater I have is the KH one and it can float or be submerged .Found my pond is warmer because it was built closer to the septic tank and it gets heat from that .

 

[waynefrcan]

I think he's wrong also. I'm actually tomorrow buying a thermometer and will chuck it in the deep part and get a reading. Pull it back out with a string. Right now is thin layer of ice. I'll also take some readings as soon as the pond ices over solid.

 

[sissy]

I have a foating one and a foating one that i tied a weight to and a string tied to it to bring it up to see bottom temps .My pond top water is at 65 degrees and bottom is around 72 degrees at the deepest end and that is the part that is closer to the septic tank .

 

[mtpond]

Last year was my first winter with my pond. I was really worried about leaving my fish outside over the winter. I used an air pump with a 7 inch defuser that I put on a shelf in the pond which was down about a foot and a half. I also sunk a stock heater thinking it might help to add some heat to the bottom and often thru the winter I would see fish laying around the heater. Don't really know that it helped much but it made me feel a little better. I also monitor the temp on both the bottom and top of the pond. This morning the bottom was 39.5 and top was 32.

 

[callingcolleen1]

Never tested the water at the bottom for a long time, I can see its warmer cause the fish go deep when the temperature drops outside. I think I will look for my "dropping thermometer" that I have not used for a while, and test the bottom just to see.

Wayne it will be nice to find out how your "star trek" way works out, and if it is cheaper and still effective, to run than the 1500 watt heater standard heater.

My surface water tonight was 34 degrees. Fish look fine, one small fat goldfish was eating something on the bottom.

 

[waynefrcan]

Cool MTP! Those are the exact temps needed. 39.5 with the bottom heater?

 

[mtpond]

Wayne I haven't put my heater in the bottom yet. I want to run my waterfall as long as I can cause it keeps filtering the water and taking the leaves that are falling off the tree out of the pond. Last year I covered it but this year I haven't. I have just been netting the stuff out that hasn't went into the skimmer. I think last year I had a lot more leaves and pine needles that fell into the pond. Next week it looks like temps in the 40's and 50's. Yes snow will melt and I can get lawn furniture an fountains put away for the winter.

 

[waynefrcan]

Great, what type of thermometer do you use? How close is the defuser to the bottom and to the heater?

I should also add that the expert also mentions with the 12" airstone, it's the micro bubbles that pull the heat from the earth. This is too funny.

 

[mtpond]

Last year I had the defuser about 5 ft. from the heater. This winter maybe I will experiment and put it closer to the heater to see if it makes a difference. I will test it on days when the temp. outside is close to the same.
This is what I use for the top of the pond, it is made by Taylor.

This one is for the bottom of pond made by La Crosse Technology. It is housed in the container that my air pump is in. Had this same one last winter but the capillary line got broken. I believe a fish may have bit it. So with this new one I enclosed the line in air tubing.