Theo-
Very good examples and descriptions!
goldenpond- Because the colder water in winter retains more oxygen and the entire aquatic habitat is slowed to a hibernation pace, not as much aeration is required as is needed during summer.
The aeration system name is not named correctly. It should be called a de-icing system during winter and a circulating system during spring, summer and fall. The transfer of oxygen is less than 5% in the bubble. The actual aeration effect takes place at the surface where the "bad" water that contains Hydrogen Sulfide and Carbon Dioxide gases is released and since this water is low in oxygen it pulls in oxygen molecules and eventually circulates this oxygen rich water back down to the bottom.
By gentally moving the water at the surface during the winter, the ice is unable to build. This allows the sun to penetrate and allows hydrogen suflide and carbon dioxide to escape.
The problem with your long trench is the fact that either by a Windmill or by an electric compressor, you will be compressing atmospheric air that will contain water. That water will build up in the dips of the feeder tubing and if this tubing is not burried below the freeze line, these areas will freeze and plug the line.
You need to make sure you have one of the following so you do not have an ice build up in the line to the lake:
1) a positive slope down hill with no dips
2) the line burried below your freeze zone
3) insulate the line with a hot water insulation.
The windmill company has an option of an injection of a chemical to deice the line if it does become blocked as well.
I have used rubbing alcohol to remove plugged lines in the past. Since it is such a small amount, it was immediately diluted once it entered the water.
I even had one Aquaculture Customer in the mid 90's who did not heave my waring about line freezes and his entire brood stock pond froze over. He whent to extremes and poured blue dye on the snow and ice so the dye would retain the heat from the sun and help to melt the ice. He also used the alcohol idea and it worked.
