My first diving experience was in mined pits in E. central Okla back in the late 60's. If we dove below 10' or so it was freezing

Same thing diving Toledo Bend lake here in E Texas and the lakes in Ark. just too darn cold for me. I like the warmer Caribbean waters

I am going to give your thinking some serious thought this summer using the diffusers. I need to keep the waters a little cooler but maintain the DO as best I can. I keep thinking what DD1 says, your not a pond myster till you kill some fish, Trying to avoid all that!