The latest brs video states you want a closed loop in your dt or in between your sump and pushing to the dt. Anything else and you are wasting your money and time. I dont have a manifold and not sure how they work but as long as its returning to the dt and you can measure your flow to the UV you are good. Apex makes it easy with their flow meters and cor15. You wouldnt need the cor15 with your manifold though as you would manually adjust the ball gate. One benefit to the cor15 is that you can run your full gph to the tank lights on and then slow it down to kill all the protozoas during lights out. With a manifold, this isnt happening.