Bill,
I have aerated my brood ponds several times in the past and have that data available. In short, I can turn them over in 20 minutes using Kasko's 12V DC aerator. I have tested a 3/4 HP aerator in the big pond as well and the area it oxygenates is substantial in 13 feet of water during the hottest part of the summer. I believe it is due to the power of the plume that it is able to draw bottom water up. If I had used a smaller pump, I do not know if I could influence the bottom of the pond during the hottest parts of the summer. I am willing to set up that aerator again and test it in different depths of water if you could use the data.
About my thermocline, I have gathered data every year and when the big pond started, I had a thermocline around 11 feet. The pond was only half full when I got my meter. As the pond filled the thermocline remained around 12 feet. As the trees in the north end (shallow end) started to rot away and allowed for more wind action on the pond. I have seen the thermocline closer to 14 feet until August when the winds drop substantially. Then in August, I see the thermocline back at 11-12 feet (nine feet was the worst I have ever seen and that was very short lived). As soon as the winds pick back up in Sept, the thermocline will drop to 14 feet again until the water temps drop an we have more mixing for the winter.
I am trying to setup a small aeration system in the deep end of the pond to raise cold stagnant water from the bottom during the summer months to cool the top water and lower the thermocline. This system will be solar and wind powered. The trick is to have enough power available to run 24/7 (think large batteries for the 8-10 amp draw). With any luck, this season will be the one that sees this project running. More data will follow.
