Pond UV filter

[Nigse]

I have been running a UV filter fed by a pump in my small garden pond (approx 3,500 Litres) for quite a few years. The Water has always been a bit murky with large amounts of green sludge being generated during the summer months (checks on the chemical balance always indicated no problems in that respect) This sludge - consisting of fine particles - would, as well as being picked up by the bio-filter, either settle or "hang" in the water when disturbed by the fish. About 2 months ago I managed to break the UV lamp housing and as a temporary measure by-passed it, within days the water was clear (even during the hot, clear days of this July) and the sludge in the pond has reduced to virtually nothing most of which, as would be expected, is being successfully picked up by the bio filter. As no other conditions have changed (fish feeding regime, plants, water top up etc) It appears that the UV filter may have been causing more problems than the good it was supposed to be doing! Has anybody else had similar experiences or able to offer an explanation as to why, apparently, the UV filter has been causing problems?

[roz.ronly]

I had the same problems with my pond 1000 gallons. Murky despite the UV lamp and large turbo style filter box. I think it's because of the hot Summer and unable to cope with sludge. as per instructions, I cleaned the glass twice a week - shocked at the sludge in the UV. I cleared the sludge from the top layer in the filter box regularly. Still it could not cope. Finally, I pumped out half the dirty pond water and replaced it with new. Totally cleaned out the filter box. WOW! what a difference - crystal clear water in 1 hour. I do think it's the length of the hot weather making it necessary to keep on top of the husbandry.

[Hard@it]

remember UV lamps do not last long, and although it may light up it may not be givning of UV to the water. They must be renewed every so often. Also remember that blanket weed and some other growths actually thrive on water that is correct and clear for letting sun assist growth, so your filter may be working and making the water perfect for this.