Wavemaker and Circulation using powerheads

[rohnds]

I am in the process of designing and builting my own wavemaker / ciruclation unit to remove any dead spots in my tank. I found two unsed and powerheads rated at 200GPH. I want to use these two in design rather than buying one rated more than 400GPH.
You probably know my next question. I have connected my 2 powerheads using a PVC pipe. From the blue arrow, you know the direction of the waterflow. What is the water flow coming out of the small opening at the middle (assume exact middle)? Will it increase or decrease? Or would the 2 powerheads cancel out at the middle? Or would the pressue buildup due to the 2 powerheads pushing water in the opposite directions create an increase in flow rate at the middle? Even if doesn't increase flow rate, would it increase the velocity due to pressure buildup?

http://www.geocities.com/aquariumscience/powerhead1.JPG

Rohn

[blueboy]

i would be inclined to say that this plan would reduce the overall efficiency of the powerheads, but i'm not sure i understand what you are trying to accomplish by plumbing them together that way. just trying to make a 400GPH pump out of 2 200GPH pumps? a 200 GPH powerhead is plenty for eliminating dead spots, or several of them rather. just hide them behind your rockwork, hook them up to the wavemaker/timer, and you've got it. i have a couple of MJ250's(?) behind my rock, hooked up to my wavemaker. it works great. when i first put them back there, they each blew out a cloud of debris the first time they cycled on, but now it's all nice and clean back there.