I don't have an answer, but do have an idea/question.
Has anyone tried a pond of this size with a liner or tub and then used a hand pump to suck up the poop and muck from the bottom? I imagine it wouldn't get the pond 100% clean but maybe it would extend the longevity of the water if done regularly? A deepish pond might work better so that there is space for the sediment to settle.
I don't have ducks yet but was considering this. Then, I'd take the muck I pump out and use it on fruit trees.
Thoughts? I'd love to hear criticism or ideas before I try this.
