Ok DrLuke...This is where I think it starts to get good. Again, these are my experiences and would need to be validated by others....
1. We were able to drive the DO up at a rate not seen by any intermittent bottom diffuser system (under ice covered waters). This is point one and not too shocking when you really understand how O2 is absorbed into the water column. The forced air inside the hatch is a significant amount of O2 over a 3-4hr run time. We figured the 4 square feet, with the forced air and the water movement from below inside the hatch, would be equivalent to a 20' diameter hole of open water.
2. How we used the hatch to deliver air and Cleated Copper into the water column. We were able to slow the BOD. Significantly enough to get a 3 ppm gain in 300,000 gallons of water in less than 8hrs (the series of tests we performed in stained water at night, eliminating photosynthesis O2 production and a YSI Optical DO meter was used).
I know what the experts are going to say and they are right, I don't have enough scientific data to support these statements. But here is what I think is happening...
Intermittent aeration (less than 6hrs/day run time) under the ice, in Eutropic waters, the bacteria on the pond bottom are getting enough O2 to reproduce and actually flourish. By mid to late winter they are consuming most of the O2 and no matter how much is replaced, with a 6hr run time, the bacteria multiply at a rate that makes the O2 gain zero to negative. Once the ice comes off, very large quantities of O2 diffuse into the water column, UV light penetrates the bottom and the DO jumps
Beneficial bacteria,a Eutropic ice covered pond, with intermittent aeration....not good for the fish population, IME (in fact we killed 2 test ponds last year with it)!
Last edited by MNFISH2; 01/11/19 07:35 PM.
