lvsuckerfish
g funk
yeah it will pull from the sump and return in the sump there is no difference as to what area you will want to pull water from that will go through the reactor you will want to put a T in the return line and a small ball valve there should be one on the reactor on the input side of the reactor to control flow. I believe it is a more effecient way to run equipment then having power heads all over the place. I have always pulled mine from or after the sump area. as the cleaner the water the less clogged the reacto will become.