I normally leave my UV
running 24/7. The problem with this is if the flow rate is too low, you water will heat up and if it is too fast, the UV
will not be effective enough. I believe what Tim said on 100gph is about right.
is sometime not effective against ich. I recently had ich whilst my 8W UV
ran 24/7. I gave my fish a fresh water dip but that would only remove the parasite on its body. The parasite is still in the tank and going through its life cycle. The parasite can only be killed if it is carried off with the water into the UV
, but if the parasite encyst on the substrate or LR
, then the UV
will not be able to kill it.
I had to eventually move all fish into QT
and apply hyposalinity. The main tank must also leave to fallow for more than 5 weeks. I have recently upgraded my UV
to 16W. This should improve its effectiveness, but is still no guarantee IMO