Really really frustrated with hang on overflow- please help

[harpua2002]

I recently picked up a 4 year old 29 gallon setup with a 20 gallon sump and hang on overflow. It's a CPR or CPR-type, I don't know what model. I was using an Aqualifter pump with it and then the pump stopped sucking water a couple days ago. I happened to be in the room at the time and was able to prevent disaster. I was able to pick up a couple of used Aqualifters (thanks Fish Scales!) and it seemed ok for a while. Then last night I noticed the same thing again, the Aqualifter wasn't able to suck the air out of the overflow and the tank almost flooded. I've been Googling and searching here and RC and saw that some people use Maxi Jets connected to the overflow instead of Aqualifters. I tried a Maxi Jet 600 (the biggest one I have here) and it seems to be working for now, but I think the overflow is slowly starting to fill with air- maybe I need a bigger Maxi Jet? Maybe the powerhead idea is no good? I'm really at a loss here and I'm frustrated that I can't get this working. Any thoughts are really appreciated!

 

[rugdog65]

I have ran a hang on overflow on different tanks for years but never with any kind of pump at all. Never any problems at all. just start a siphon with a peice of airline tubing in the u-tube and let it go.

 

[harpua2002]

The one I have has a fitting on top that you attach a piece of airline tubing to. I have started the syphon many times using that tube before plugging in the pump and gotten many mouthfuls of tank water as a result. LOL. I can get the syphon to start but then it slowly fills with air.

 

[ichthyoid]

harpua2002;464346 wrote: The one I have has a fitting on top that you attach a piece of airline tubing to. I have started the syphon many times using that tube before plugging in the pump and gotten many mouthfuls of tank water as a result. LOL. I can get the syphon to start but then it slowly fills with air.

If it is filling with air then (in my experience anyway) you have a leak. I used siphon type overflows years ago, but now only use drilled tanks with in-tank overflows which are gravity fed and fail-proof. Fill the siphon tubes with air and hold under water to see where the leak(s) are.

 

[roundman]

How long is the tubing from the fitting to the aqualifter and from the aqualifter out. There is a limit to what this pump can do. I had to shorten my aqualifter tubing to get it to work.

 

[brianjfinn]

Yeah, it sounds like either you have a leaky siphon or your pump isn't keeping up with the siphon. Check the overflow for leaks, and if that doesn't work, try a bigger pump.

 

[harpua2002]

ichthyoid;464353 wrote: If it is filling with air then (in my experience anyway) you have a leak. I used siphon type overflows years ago, but now only use drilled tanks with in-tank overflows which are gravity fed and fail-proof. Fill the siphon tubes with air and hold under water to see where the leak(s) are.

Uh oh.

roundman;464378 wrote: How long is the tubing from the fitting to the aqualifter and from the aqualifter out. There is a limit to what this pump can do. I had to shorten my aqualifter tubing to get it to work.

It's about 8 inches long.

 

[roundman]

mine is longer than that so I would start looking for a leak.

 

[fishwhisperer]

I had a CPR overflow and it was nothing but problems. I bought a Lifereef and it was problem free...just my .02

 

[harpua2002]

Honestly, scrapping the sump and buying a HOB skimmer is starting to sound pretty good. I have never used a HOB overflow before and I've been surprised at what a pain it is. I wish I could put this in a drilled tank but I don't have one.

 

[roundman]

This is my second one and have never had any trouble out of either one. I have the overflow go to the basement with about 200 gal water in the system.

 

[harpua2002]

Ok, I feel like an idiot....

I still have no idea why the Aqualifter pumps aren't doing the job. I think I'm just going to set those aside for now. I realized a little while ago that I put the piece with the hole for the venturi backwards onto the powerhead. Once I fixed it, it seems to really be working pretty well. I think I'm going to replace it with a 900 or 1200 though and see if that helps.

Thanks everyone!

 

[ichthyoid]

harpua2002;464576 wrote: Ok, I feel like an idiot....

I still have no idea why the Aqualifter pumps aren't doing the job. I think I'm just going to set those aside for now. I realized a little while ago that I put the piece with the hole for the venturi backwards onto the powerhead. Once I fixed it, it seems to really be working pretty well. I think I'm going to replace it with a 900 or 1200 though and see if that helps.

Thanks everyone!

Believe me when I say, if you stay in this hobby long enough, sooner or later you do something that makes you feel like 'an idiot'. We have (or will have) all been there.

 

[smoothie]

Yep just a basic syphon style overflow (w/o pump) will work forever beautifully. I have it on the 100 and love it. Will love the overflows on the 180 even more although I hate the room they take up

 

[harpua2002]

Gotcha. I'm hoping the Maxi Jet will make this one reliable enough at least for a weekend getaway. Everything's fine this morning but I'll definitely be keeping an eye on it. Still stumped about the 3 Aqualifter pumps that aren't working out when a ton of other people use them but oh well, it's one less plug in the power strip.

I'd consider upgrading the overflow box but we have a spare 29 sitting in the garage so it would be a ton cheaper to just have someone drill it for me and then swap tanks. Of course, I'm not exactly itching to move everything over so I'm hoping this thing just works.