Thanks for the reply Eric. FYI, I will be using a trash pump to drain the pond. This pond has bottom diffusers which should address the water quality problem. Based on loss of water volume overcrowding might/would be a red flag. Of course I could also look at this as an opportunity for the LMB to clean up some of the BG spawn from last year.

I'm going to reread your links and give additional thought to how much water I should remove. Thanks again.

Russ