minibowmatt":2sad3t2z said:I moving vertical a max of 5 feet. I think I will split the return with a SCWD and empty to the tank via a dual locline. I used the head calculator and i think i will be getting around 650gph at the tank returns. So maybe the 1" will be ok? Or should I go for the 1 1/4" and be safe? I could always add a ball valve on the return line. How much back pressure can the mag pumps handle?