[Baz]

Hey Patrick......those are beautiful water features!

I'm not a "pond" guy but couldn't you retrofit the waterfall with the proper filtration system as you would any other water feature similar in nature?

There's got to be oodles of technical info available online and from suppliers with lots of options.

I never got into water features as part of my business. There are a few outfits in our area that specialize in them. I do think they are very cool if designed right and kept up.

Sorry I couldn't be of more help!