Aqua 80 watt UV Sterlizer

[Oakie]

Picked one of these up from someone getting out of the hobby.

The intake/return on this unit is 2" - does that mean if I reduce the size of pipe going to the intake from the pump I will diminish the unit's capability? I imagine the answer to that would be yes as I'm putting less water through, but does it to a point where it's not useful?

 

[DarG]

The slower the flow the longer the contact time the higher the does of UVC the higher the kill rate. But you have to balance that with enough turnover.
It shouldnt be a problem reducing down usually. I recently read that 2 - 3 X per hour tank turnover is good range with a properly sized unit for the water volume if you are using it as a clarifier ... to help reduce algae growth on the glass and substrate and keep tank water clear.
I run about 2 1/2 or 3 times tank volume per hour through a 25 watt on my 90 gallon and it does a great job as a clarifier. So I think thats a good guideline. But I have also run slower flow rates, like 1X per hour and also had good results.
So if you can run the systems water volume through the unit a couple times per hour with reducing the input and output down you should be fine.

Not an expert on UV but I have used them for a long time. But I use them as clarifiers, not as a cure for ich or a preventative for problems ultimately caused by poor tank husbandry on my part.