Closed Loop Pump Question

[gfishguy56]

For more circulation, I built a closed loop system with 3 returns; one on each end and one in the middle of my tank. I had an extra Mag 7 laying around, but it was barely strong enough to make a ripple in the tank. I then bought a Mag Drive 1200, thinking it would be strong enough, and it isn't; stronger than the mag 7, but not by much. I actually use a Mag Drive 1200 running my dual megaflow with plenty of pressure/current. I'm seeing now that a 3rd return drastically reduces a pump's pushing abilities.
So, how big of a pump do i need to actually create more movement/current? I don't want so much pressure that my fish are plastered against the glass, but i would like as much comfortable turbulence as possible. Any help is appreciated, thanx.

[RMPD109]

For a reef setup your water movement should be about 20x hr. The movement at the surface may not look like much but below it may be fine. Also once you split the closed loop into 3 outputs the pressure at each output is greatly reduced. You still get the same turnover but it is dilutted into three areas. I hope I made sense in my rantings.

[gfishguy56]

You made sense, i think. But when i feel the pressure from the returns, it feels weak and i don't feel it at all just 6 inches away from the return. Does that make sense? So how can it be the same turnover? I'm so confused, but i am a little slow

[RMPD109]

try thinking about it in terms of quantity instead of pressure. You pour one cup of water into a tube. One cup will come out the other end. Now take the same tube but put a y in it before the water comes out. Now there are two outlets giving 1/2 a cup each. Total is still one cup but at each outlet it seems small as it is a 1/2 cup.

Relate that to flow instead of volume and see if that helps any. One way to give a bit more pressure is to restrict the size of the output tube. The smaller the tube the more forceful the water will exit through it.

[Brad]

In fact, I think what you've produced is very good. You want lots of water movement (volume), without a lot of water pressure. I think that is why really nice PHs have very large diametre outputs.

[gfishguy56]

i understand now what you are saying from your example. Thanx to both of you for your help and for saving me the money on a stronger, yet more expensive, pump.