Well I don't have a deep cold water layer so I don't have that to lose. My temps are the same, during the spring through fall, all the way through the water column.

I guess that you're saying that as my pond gets older the sh!t piles high and robs oxygen? I haven't lost any this year and did lose two last year but those were before the fountain.

I'm getting ready to expand this pond again and I will have the new portion over 20' deep. This new portion will have very little water circulation from the aerator as it will be around a dog leg. I'm hoping to mostly keep that area stratified and use it as a "heat sink". This, I'm hoping, would keep a cool area of water right next to an oxygen enriched area that would be essentially "air conditioned" by the deep water.

I don't know if what I'm saying sounds nuts or not but I'm gonna try it.

I just got a new pond, I made it twice because I aint so bright.