They have been mishandled because they are most assuredly poorly designed. However I applaud your efforts and perseverence. Tough spot my friend, I do this kind of thing every day and yet I can't think of any solution other than a complete overhaul and redesign. Shallow large ponds without filtration are algae nightmares. And you solve one problem but create another. Plus the obvious extremely limited budget, and cost too much too refill? I'd counter, it's going to cost way more not too drain and sanitize. You almost have to make them no life poison ponds just to get them not to crash. Your a better man than me Gunga Din.
