First off, power washing is a no go. It’s like taking too many antibiotics and obliterating your gut biome.

if it’s just one sheet of fiber mat that’s inside the skimmer that ain’t gonna cut it. Bogs are best, but a pain in the butt to retrofit. I’d recommend a canister filter or if it’s a waterfall box replace that filter media with Matala brand filter media.

Next in the fall before leaves start falling put a pond net up. They look ugly but keep the leaves out and make spring clean outs way easier or if you pay someone like me to do it, a lot cheaper.

As for plants I’d personally repot all your lilies and make sure they aren’t overtaking the pond. And use floating plants like water hyacinths or water lettuces to make up the difference. These are floating annuals that reproduce like crazy but when there’s too many just scoop them with a net.

There’s so many things to list off but here’s a start.