Located in N. Illinois.

I have a 120 gallon pond. 20 gal upper, waterfall, 100 gal lower pool. Too
many fish, they grew.....

I know the rule is 1in per 10gal. So I have about five times too many fish.

Could not keep the algae under control.

Bought a 500gal UV canister filter Nursery Pro Ultra Clean. Problem fixed.
I clean it about once every three weeks. The water is crystal clear.

Clean the pre-filter about once a week, mainly leaves.

Martin