removing biologicals from the pond decreases the nutrient load. filtering
algae wont work like with UV unless there is some way to physically remove
the stuff before it breaks down and the nutrients end up back in the pond.

a caution. bacteria like ridX are usually of the anaerobic kind, that is
they crank out some quite toxic compounds in teh process of breaking
organics down. really good aeration and flow of water thru the pond can
keep mulm to a minimum. this is now my 7th year of the pond and I can still
see the folds on the bottom of my pond (also the pea gravel they sucked out
of the lily pots). the mulm from my pond ends up in the veggie filter where
I clean it out once a year in fall.

I also think the mulm problem has declined since I started feeding really
high quality koi food. Ingrid