Surging overflow

jeffesaurusrex · 05/02/2012, 09:01 PM

I've got a pre drilled 75g tank with a durso style standpipe overflow. It sits in a chamber with a floodgate. I'm using a mag 9.5 pump, and the drain is 1".

The overflow is surging - I can hear it and it sounds like waves, and when I look into the overflow chamber I can see the water draining down below the drainpipe inlet and then rising back over it. I'm thinking maybe there is a siphon on this drain and my pump isn't enough to keep up with this? I tried throttling the pump back, it just makes it worse.

Any suggestions?

evsalty · 05/02/2012, 09:09 PM

Sounds like you do not have an air hole in the top of the stand pipe. For a Durso to work there needs to be an air hole or else you will create a siphon like you said it is doing.

jeffesaurusrex · 05/03/2012, 04:46 AM

There's an air hole, maybe it's too small? It's about a 5mm hole. If I put my finger over it, it makes it way worse. It's also kind of whistling sometimes.

sirreal63 · 05/03/2012, 07:24 AM

If this is a Durso style or Mega Flow, it is an open channel drain and will effectively flow 600 gph, when you try and push more through it, it does the flushing thing. You are trying to push too much water through it.

05/02/2012, 09:01 PM	#1
jeffesaurusrex Registered Member Join Date: Jul 2011 Location: Terre Haute, IN Posts: 322	Surging overflow I've got a pre drilled 75g tank with a durso style standpipe overflow. It sits in a chamber with a floodgate. I'm using a mag 9.5 pump, and the drain is 1". The overflow is surging - I can hear it and it sounds like waves, and when I look into the overflow chamber I can see the water draining down below the drainpipe inlet and then rising back over it. I'm thinking maybe there is a siphon on this drain and my pump isn't enough to keep up with this? I tried throttling the pump back, it just makes it worse. Any suggestions? __________________ -Jeff Current Tank Info: 29g Biocube - StevesLEDs - MP10 - Apex - Tunze

05/03/2012, 04:46 AM	#3
jeffesaurusrex Registered Member Join Date: Jul 2011 Location: Terre Haute, IN Posts: 322	There's an air hole, maybe it's too small? It's about a 5mm hole. If I put my finger over it, it makes it way worse. It's also kind of whistling sometimes. __________________ -Jeff Current Tank Info: 29g Biocube - StevesLEDs - MP10 - Apex - Tunze

05/03/2012, 07:24 AM	#4
sirreal63 Go Spurs Go!!! Join Date: Dec 2004 Location: Meadowlakes Texas Posts: 13,357	If this is a Durso style or Mega Flow, it is an open channel drain and will effectively flow 600 gph, when you try and push more through it, it does the flushing thing. You are trying to push too much water through it. __________________ Jack No One has ever been seriously injured by using the search function. Alcohol, Tobacco and Firearms should be a convenience store, not a government agency. Current Tank Info: Reefing the Pentagon.

05/02/2012, 09:09 PM	#2
evsalty hmmmmmm Join Date: Jan 2009 Location: NW Mesa, AZ Posts: 3,531	Sounds like you do not have an air hole in the top of the stand pipe. For a Durso to work there needs to be an air hole or else you will create a siphon like you said it is doing.