Overflow faster than return?

magnon · 02/15/2007, 11:26 AM

I installed a DIY overflow in my 120 gal with (2) 1-1/4"durso standpipes reducing to 1" and split 8" pvc pipe overflows. It seems that the flow from the overflows is faster than the pump (Iwaki 30 XLT) is delivering through the return. I currently have 1 of the drains cut off. With both open the sump level rises and the tank level falls. Any Ideas?

rcgates · 02/15/2007, 11:30 AM

a faster pump, which would cost a few $ or place a gate valve on the
drain line to slow the drain down and balance the flow.

shag26272 · 02/15/2007, 11:33 AM

overflow is supposed to be faster then return, if it was the other way around your tank would overflow and there would be no water left in your sump

luke33 · 02/15/2007, 11:34 AM

How low are the inside boxes for your overflow. The teeth may be to low, try raising them up to reduce flow, your return should keep it where it wants it. Is this a utube diy or what?

shag26272 · 02/15/2007, 11:39 AM

I agree with the teeth, its not your pump your tank water level shouldnt be falling unless the teeth are too low

magnon · 02/15/2007, 11:44 AM

RCGates- yes I thought about upsizing the pump but it seems to me that the drain should overflow the same flow rate and volume the return supplies, but that's not the case.

Shag- yes I agree but if I open both drains, the tank level falls and the sump level rises.

Luke- No Not a U-tube, the tank is drilled through the back. I thought the return should maintain the level also but it doesn't with both overflows running. Instead the tank level drops and the sump fills. I'm afraid to leave it open for fear of overflowing the sump.

Thanks all for the responses.

zoomfish1 · 02/15/2007, 11:47 AM

Solution is a ball valve on the drain line before it enters the sump. Dial it back until the drain matches the return pump. Easy fix.

shag26272 · 02/15/2007, 11:49 AM

raising your teeth will help also, like was suggested before

magnon · 02/15/2007, 11:49 AM

zoomfish- Yeah thats essentially what I'm doing. I have ball valves on both drains. But like I said, it seems to me that the drain should only carry what the pump delivers to it. I do have to throttle the drains but I don't understand why.

luke33 · 02/15/2007, 11:51 AM

Yep, it its drilled use the ball valve. I'm guessing you have no teeth on it, correct. So it will pull to much water, there's nothing restricting your flow.

shag26272 · 02/15/2007, 11:52 AM

try putting some flat pieces on the bottom half of your teeth to cover them, I think they are just cut too deep maybe and its making your tank have a low water level

magnon · 02/15/2007, 12:03 PM

OK sounds like the "raising teeth" solution is the consensus. I'll give that a try.

luke, you are correct, I'm using a weir or notch cut in the overflow rather than teeth. Should give the same effect though. I'll try raising it and see if that helps.

I appreciate everyone's input

nhlives · 02/15/2007, 12:10 PM

When setting up the system has to establish an equilibrium. When I first set up it took a bit of adjustments (cutting down flow and adding water to the sump) before things smoothed out.

02/15/2007, 11:26 AM	#1
magnon Registered Member Join Date: Dec 2006 Location: Va Beach, VA Posts: 58	Overflow faster than return? I installed a DIY overflow in my 120 gal with (2) 1-1/4"durso standpipes reducing to 1" and split 8" pvc pipe overflows. It seems that the flow from the overflows is faster than the pump (Iwaki 30 XLT) is delivering through the return. I currently have 1 of the drains cut off. With both open the sump level rises and the tank level falls. Any Ideas?

02/15/2007, 11:33 AM	#3
shag26272 Registered Member Join Date: Sep 2001 Location: New Orleans, LA Posts: 3,088	overflow is supposed to be faster then return, if it was the other way around your tank would overflow and there would be no water left in your sump __________________ .

02/15/2007, 11:39 AM	#5
shag26272 Registered Member Join Date: Sep 2001 Location: New Orleans, LA Posts: 3,088	I agree with the teeth, its not your pump your tank water level shouldnt be falling unless the teeth are too low __________________ .

02/15/2007, 11:47 AM	#7
zoomfish1 Registered Member Join Date: Mar 2005 Location: Claremore, Oklahoma Posts: 1,659	Solution is a ball valve on the drain line before it enters the sump. Dial it back until the drain matches the return pump. Easy fix. __________________ Zoomfish Current Tank Info: 75g RR, dsb w/90 lbs sand, 150 lb live rock, anemone & LPS tank

02/15/2007, 11:49 AM	#8
shag26272 Registered Member Join Date: Sep 2001 Location: New Orleans, LA Posts: 3,088	raising your teeth will help also, like was suggested before __________________ .

02/15/2007, 11:30 AM	#2
rcgates Premium Member Join Date: Dec 2006 Location: Central Coast CA Posts: 319	a faster pump, which would cost a few $ or place a gate valve on the drain line to slow the drain down and balance the flow.

02/15/2007, 11:34 AM	#4
luke33 Moved On Join Date: Dec 2006 Location: Indiana Posts: 8,375	How low are the inside boxes for your overflow. The teeth may be to low, try raising them up to reduce flow, your return should keep it where it wants it. Is this a utube diy or what?

02/15/2007, 11:44 AM	#6
magnon Registered Member Join Date: Dec 2006 Location: Va Beach, VA Posts: 58	RCGates- yes I thought about upsizing the pump but it seems to me that the drain should overflow the same flow rate and volume the return supplies, but that's not the case. Shag- yes I agree but if I open both drains, the tank level falls and the sump level rises. Luke- No Not a U-tube, the tank is drilled through the back. I thought the return should maintain the level also but it doesn't with both overflows running. Instead the tank level drops and the sump fills. I'm afraid to leave it open for fear of overflowing the sump. Thanks all for the responses.

02/15/2007, 11:51 AM	#10
luke33 Moved On Join Date: Dec 2006 Location: Indiana Posts: 8,375	Yep, it its drilled use the ball valve. I'm guessing you have no teeth on it, correct. So it will pull to much water, there's nothing restricting your flow.

02/15/2007, 11:52 AM	#11
shag26272 Registered Member Join Date: Sep 2001 Location: New Orleans, LA Posts: 3,088	try putting some flat pieces on the bottom half of your teeth to cover them, I think they are just cut too deep maybe and its making your tank have a low water level __________________ .

02/15/2007, 12:03 PM	#12
magnon Registered Member Join Date: Dec 2006 Location: Va Beach, VA Posts: 58	OK sounds like the "raising teeth" solution is the consensus. I'll give that a try. luke, you are correct, I'm using a weir or notch cut in the overflow rather than teeth. Should give the same effect though. I'll try raising it and see if that helps. I appreciate everyone's input

02/15/2007, 12:10 PM	#13
nhlives Registered Member Join Date: Oct 2006 Location: Florida Posts: 247	When setting up the system has to establish an equilibrium. When I first set up it took a bit of adjustments (cutting down flow and adding water to the sump) before things smoothed out.