Someone gave me a potentially great idea:

What if:

1. I allow ice to form a layer at 5" thick over the pond surface

2. Then,i use the hole vent in the ice to place a tube that i will use the tube to siphon off 1" of water from under the ice, thus forming an air space between the water surface and the ice above

Will the air pocket BETWEEN the low[ered] water surface and the ice above keep the water below the ice insulated so that it will not freeze.

I would think that since my pond is 10 x 5.5 that a little hole in the sheet of 5" thick ice would not let all the warmer air out. (The hole won't close because there won't be water touching it to close it and 5" is thick enough not to break.)

[Additionally, I can drill a small hole into the cement side of my house and put the air stone pump inside and run a tube through the hole to the outside where warmer air will be pumped into the pond so that the airpocket that i will have created will keep warm enough so that even though some warm air escapes through the vent hole, new warm air (regulated amount) will be restored with the airstone.]

You also sent me an e-mail regarding this. I wish I had a sent e-mail folder because I could just paste the response.

I mention this method at http://www.fishpondinfo.com/winter.htm#keep under #7.

This method may work with larger ponds. My 1800 gallon is not deep enough. My worry would be that if I lowered the water from 26" max to say 16" after water removal and then that layer froze (two separate ice sheets), the fish would be in real trouble. I need all the volume I can get. Around here in MD, temperatures fluctuate so so do ice levels.