2 Screens, no growth in one of them

[wormside]

Hello.

I have 2 screens in my system. Because of the layout of my sump I put them in diferent configurations, although both have the same flow and light, one of them has a significaly larger amount of algae than the other.
In the one with less growth, green algae never has spawn, but in the other it takes no time to algae appears again after the cleanings.

I think the problem could be the water flow, I know I mentioned both has the same amount because a "T" conection that came from the main tank, but the one with less growth is made from a pvc tube with a cut in the middle (longitudinal) where the screen is inserted, like the initial scrubber design posted in this forum.
Because of this half of the watter runs to the back of the screen where no light is present and the other half is where minimal growth is present.

What can I do to make this screen to grow more algae just in one side where the light is present? the design with a cut in the middle may not work for this case right?

Please advice.

Good growth all flow one side:
http://img30.imageshack.us/img30/5678/dsc00242vy.jpg (http://img30.imageshack.us/i/dsc00242vy.jpg/)

Minimal growth flow divided between two faces of the screen:
http://img30.imageshack.us/img30/4571/dsc00244kk.jpg (http://img30.imageshack.us/i/dsc00244kk.jpg/)

System layout
http://img30.imageshack.us/img30/8959/dsc00246uz.jpg (http://img30.imageshack.us/i/dsc00246uz.jpg/)

[SantaMonica]

Well of course the 2X flow is going to get better growth. Why not just shut off the slow screen.

[wormside]

I dont wnt to shut off that screen becaue is significally larger than the one that has algae growing...

May be if I put that screen with a powerhead or something to get more flow... I dont want to do that because the addition of another pump, I thought it would be a better option or layout for a single side screen..

Anyone...?

[SantaMonica]

Then either convert your two-flow-sided screen to one-sided, or, shorten the pipe to half the size so the slot it only half as long, and cut the screen to match it. Either way, flow will increase, and filtering will too.

[wormside]

Thanks!
But how can I convert that screen to "one sided"? is there a way to cut the pipe so the water flows only from one side? May be if I rotate a litle bit that pipe so the screen itself cuts out the flow one one side mmmm....

OK, let me try that, if that doesn't work, I'll cut that pipe to get more flow both sides.

Rgds.

[SantaMonica]

Put the screen on the back of the pipe, instead of in the slot.