UV sterilizer question

[aquamanathome]

How long should water be exposed to the ultra violet light for a sterilizer to be affective?
I’m afraid that my water moves to quickly.

[The Floodinator]

I have a Coralife 18 Watt and to kill parasites The recommended flow was <100gph.

[aquamanathome]

thanks, I built my own but i think i need to restrict the flow

[The Floodinator]

From what I understand the slower the better. just dont let the bulb overheat.

[Roy G. Biv]

If you built your own you could look up instructions for similiar ones for sale. Each one comes with a flow chart and what each flow rate kills. I have a 36W and it recommends 295gph for "Ultra Kill"..(unreal tournament)