I sounds like you have confirmed what I have been thinking. The thought of a complete renovation has crossed my mind, mainly because I can drain the pond and hire someone to clean up the muck and deepen the edges. I've heard draining the pond halfway for awhile can help consolidate the BG and works well? The only thing I have access to is a trash pump so I imagine that would take awhile! The decision to renovate is not entirely mine so I will have to talk the other half.

If I were unable to start over what would be the best course of action? Harvest BG and add more predator fish? I've thought about adding 20 or so HSB but have only found one place around here that sells them and it's like 2 1/2 hours away so not sure if they would survive the drive back?