Head Pressure Question

[BillB83]

Setting up a 25 watt UV on a 120 fowlr tank on its own return pump

BRS reccommends 400 gph

I am losing about 7-7.5" head pressure, 4ft vertical, 3ft horizontal, 3-90s with 3/4 inch PVC. I am missing the last step in how do i calculate GPH loss based on the head pressure loss ? Can i run a sicce 2.0 thats rated at like 568 ? or do i just pick up one of the SDCs and adjust it but still im left not knowing the exact gph ?

Thanks in advance

 

[KStatefan]

Look at the pump flow chart.

 

[BillB83]

got it

TY

 

[BillB83]

seems like the 1.5 almost does it and for a UV system wouldnt slower flow be better anyways ?