Jeff, yes it sure did help.
Geo NR Gee, Yes that is what I thought too, but the uppermost layer is going to be affected by the cold more I believe, seeing as it freezes first. I have data loggers in a couple different places right now. I will need cold water in the summer, so seeing as I have more cooling days than heating days, I might be best staying close to the bottom.
I found this link,
Heat in Lakes