The slower the flow rate the better the kill ratio. Some "higher" oragizism
(sp?) like protozoa can survive the higher flow rates of some UVs. I have a
lifeguard 25watt UV on my 240gal that shares a pump with the fluidized bed
filter. The flow rate through the UV is 200gph. It's nice and slow, which
should mean that as long as I keep a good bulb in there, my chances of a
waterborne illness is really slim.

Justin

"Starfish" wrote in message
...
Hi
I got a pro aqua (or aqua pro) 11w hang on the back UV steriliser for my
198
gallon tank...
There is no reccomendations for a maximum flow and there doesnt seem to be
anything on the the net stating this. I am a little confused as I was
assured that this 11 watt would be fine for up to a 900L tank...hmmmm