UV Sterilizer Closed Loop Importance

[Jrapa86]

Hello everyone. I currently have an 8-watt UV sterilizer hard plumbed from my sump to my DT, acting as a secondary pump to the DT, along with a direct line from a Cor pump. After reading more, I understand it's better to have a closed loop from the DT directly back to the DT.

How important is this? Does it make a big difference? Or keeping it as is in the sump should be sufficient?

Note: For some reason (I suppose due to head pressure), the Cor-20 pump (rated at 2000gph) seems to only put out about 350 gph at its maximum for me (1" PVC, 4 90 degree elbows, 4ft height - metered on an apex 1" flow sensor). I was using the UV pump in my sump to make up the difference in the lack of return flow in order to get ~10x turnover.

 

[kbnh]

I originally put my sterilizer in my sump with a seperate pump, there was visible ich on the fish

I then moved the uv into the canopy and the pump in the display, had a lot better results as the ich goes away for a while until the fish get stressed from something

in both cases I had no fish loss but their skin cleared up faster while it was in the display rather than sump

I think on my next tank I’d like a seperate closed loop just for the uv, one where the water is drawn in through a lower area of the display