filtration

i previously had two canister type filters on my 2000g pond.one was
rated for 500g and the other for 250g. i thought one was rated for 750g
but 750g was it's max flow rate. these filters clogged weekly and i
could clean them in the morning and by sunset they would be very dirty
again. i don't want to clean my filters any more than a couple times a
month.

i had one 20w uv light in place which keeps the water from turning
green and a verly large ammount of plants, almost enough to cover the
whole bootom. i also kept the fish load to a minimum, maybe a couple
dozen 4-5" goldfish or smaller.

the water quality wasn't bad but there's a lot of suspended
particulate in there, cleaning those two small filters might help out
more, but i'm not ready to do that. the water color is also yellow. i
belive this is due to the peat in the soil that i use for all my plants
but i'm not very worried about the color as i am about the floating
stuff which is very unsightly.

i have put together a 40g rubbermade tub filter. i have plumbed a 3/4"
intake and 2x 3/4" exhaust pipes which go into my waterfall. my
question, based on the above, is what kind of filter media should i
use? i currently only have bio-balls in there for biological
filtration. something for mechanical filtration would be good. i need
something cheap and doesn't clog easily. i don't care if it was
designed for ponds or not so long as it helps out and doesn't negativly
affect the life in the pond.

what would you guys say?

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