I doubt that the cloudy water is a result of mulm under the UGF. I've had a
UGF filter using powerheads on my 100gal for several years. The time I had
cloudy water was corrected by changing the feeding schedule and amounts. I
did not have to change my filtration nor vacuum out the mulm from under the
plate.

As with most cloudy water, the problem is bacterial bloom (for white/grayish
water). This is more often than not either overfeeding or a non-functioning
filter. You had mentioned that your tank was running well for 1 year, which
suggests to me that it's not the amount of filtration you have, but the
efficiency of that filtration.

Check and rinse your filters. Make sure the powerheads have the proper flow
rate as well as the canister pump. If this doesn't resolve your cloudy
water, consider your feeding amounts and schedule.

Justin

"John..." wrote in message
...
Hi,I am looking for recommendations on external canister filters.
Currently I have a 200 litre tank with fake plants and around 50
fish ranging in size from 2 4 inch clown loaches to a few neon
tetras. I am running a UGF powered by 2 powerheads operating
at a combined 300GPH.The filtration is supplemented by a
Fluval 2plus internal filter. My tank has been running for just over
1 year with no problems. Lately my water has gone from being crystal clear
to slightly cloudy/hazy. I can still see the fish ok,but the hazy water is
annoying me. I'm thinking this is due to a build
up of mulm under the filter plate,so I devised a tube that fits onto my
gravel vacuum that can be inserted under the filter plate.This does remove
a
lot of mulm,but obviously does not remove all of it.
I don't want to do a full stripdown of the tank,so I thought I could
improve the filtration by adding an external canister filter.
Your thoughts would be welcome on this.
Thanks.

John.