Closed Loop and Drainage all through large overflow?

[H20ENG]

Hi All,
I'm helping a friend with a 540 tank. I want to use a full width (36") overflow screen x 6"tall to overflow ALL water into the overflow box. Tank is 37"h so I think there is plenty of room in the overflow box. I'll draw from the bottom of the overflow for the CL and Dursos or similar for the drain.
I realize I may lose some surface skimming effectiveness by returning some of this water to the tank, but the mass turnover and huge skimmer will make mincemeat out of it when it does get there
I'm confident, but wanted to hear others opinions and hopefully, experiences.
Thanks,
Chris

 

[Acrylics]

Hi again Chris,
My main issue with this is that most overflows are inherently turbulent so bubbles are more apt to get into the CL system. Not that this will necessarily hurt anything but can be unattractive to have gazilliions of microbubbles sprayed back into the tank. I know the overflow is tall, but mandates a certain water level in the overflow to clear bubbles.

James

 

[H20ENG]

Thanks James,
I see your point. My hopes are there will not be much fall, thus the 6" deep opening to keep it flooded.

 

[nyvp]

remember also a overflow is ment to skim off just the tops oils from the surfice of the tank. why would you want to send all that back? also the more water your crashing over the overflow the more noice you make. I tried the same thing and went back and drilled in my closed loop piping. If you dont want to drill then just go over the top with 1 1/2 or 2 inch. cover it with rocks and now one will ever know.

 

[gabe3d]

The tank i have is a lot smaller than what you are planning but i do exactly what you said on my 210 gallons tank. It definetely works but you'll have to find the perfect height for the durso and make sure how much the overflow box can handle. I had a slight problem with mine because as water was moving in the overflow box, it whirled the water because of the durso and the debris would not make it in the durso pipes. I moded my durso and it is ok now.

HTH

 

[H20ENG]

Thanks guys,

nyvp,
I understand the effectiveness will be slightly diminished, but there will be so much flow, that I believe its minimal. The overflow screen willbe so large that there will be no crashing water.

Gabe3d,
Thanks, I'll keep that in mind when plumbing the Dursos.

 

[AcroSteve]

If the return is shut off, the CL pump may run dry, unless the durso is very high in relation to the overflow teeth.

 

[sophiasdad]

I do not recommend taking your closed loop supply from the bottom of your overflow. I did that and ended up drilling holes through my overflow boxes to take the closed loop supply from the tank.
It simply didn't work in my case, too much flow required of the overflow skimmer etc..
Anyway, good luck.