I've heard some real horror stories from people who maintained recirculation
systems (including commercial operators). In fact, I personally know of 3
retail and 1 wholesale establishment locally that have disconnected their
systems because of recurring disease problems.
UV is find as long as it is maintained properly and delivered at the correct
dose rate. However, most hobbyists simply don't - that's if they even have one?
A friend of mine went to the trouble of drilling holes in all his aquariums
(100+) and fitting overflows, piping etc etc, to set up a full recirculating
system. However, I talked him out of it when I told him all the downside of
having such a system. Now when I visit him I feel guilty every time I see
all the hardware not being used, but I know that in the long term I saved
him from a lot of heartbreak?.
ps - How's your Fenbenazole trials going??
Adrian.
Adrian R. Tappin
"Home of the Rainbowfish"
http://www.ecn.net.au/~atappin/home.htm