Have had pond for almost 10 years, 5000 gals, 15'x 15', goldfish only. Have had green water, but when filters (also homemade) kicked in, cleared. Last fall, found I had a snapping turtle (large) find its way into the pond, enjoying a feast. Had to drain pond almost completely to get him out. Refilled (well water) and then we got a hot spell, then turned cold. Water is terrible, green with alots of "stuff" floating. I am afraid my filters will never catch up.

Does anyone have a plan for a homemade sand filter - maybe a tub, with materials, then sand on top which can be cleaned easier than my filters? what materials for the bottom so the sand doesn't go thru. Budget is limited - am retired. Or does anyone have any other ideas - don't like chemicals.

Thanks for any help.