Overflow leak? Fixable?

[krisjoseph]

I occasionally turn off all of my tank pumps (power heads and return) in order to do target feeds of corals.

About two weeks ago I noticed that the water in my tank was dropping below the level of the overflow when the pumps were off. I thought this was impossible and noticed that the level would drop to about the level of the return outflows.

My first theory was that water was back-siphoning through the return pipes and that my check valve was failing... But when I changed my filter socks the other day I noticed that the drain into the sump stopped when I closed the valve on the pipe that comes out of the bottom.of the overflow.

As far as I can tell, there is a a leak in the overflow seam somewhere: the tank will continue to drain slowly until the overflow and the main tank are at the same level, and then it stops. By happy accident the volume of water won't cause my sump to over-fill... But the water raises right to the brim and makes my skimmer go nuts.

The workaround for now is simple: close the valve under the overflow box whenever I stop all the pumps. But that's a PITA and is not something I can account for with my Neptune programming/automation.

I'd like to find and fix the leak. Any suggestions for how I can do thus efficiently? And can it be fixed without having to drain my DT?

Thanks for any suggestions you can offer!

 

[ReeferEric]

It's gotta be a fairly large leak for you to notice. Take some pictures of the overflow, I have some ideas but it's kind of vague and hard to understand what you wrote.

 

[krisjoseph]

Thanks for the response, and I'm sorry my description is vague!

I did some more checking this morning and I know for sure there's a leak somewhere that allows water into the overflow box even when the level in the display tank is lower than the "teeth" on the overflow.

To test this, I stopped all the pumps, and then pulled the durso standpipe in the overflow.

In theory, the water in the overflow area should drain completely into the sump, and then the overflow box should stay empty ... But it doesn't. Water just keeps trickling into the overflow (probably 1-3 gallons per minute) and into the sump.

It looks as though there's a break in the seam where the overflow wall meets the rear wall of the tank, as that seems to be where the water is entering.

I tried to get some pics of this but it's quite tricky due to the fact that it's a rear-left overflow box which is in the corner of the room. I got a shot of the valve/sump under the tank, and a pic of the overflow from the front of the tank, but couldn't get a good shot of the overflow from the side that's against the wall. As I said earlier, it's a durso-style overflow box

So: assuming I'm right and that silicone seam has failed, is there any way to fix it without tearing the tank down?

 

[GHill762]

I don't know how well it would work, maybe someone else can chime in, but if you can find the area of the leak you may be able to seal it up with epoxy putty.. unfortunately if you silicone it, it'll have to stay dry until it cures (multiple days IME)..

 

[IronVulture]

Sound like the perfect excuse to upgrade to a new larger tank. I think the putty approach will only be a temporary patch and is likely to only slow the leak. Personally I would continue to use the shut off valve and save for a new tank and covert the present tank to a nice quarantine tank after the repairs are done properly with the area totally dry.

 

[GHill762]

Sound like the perfect excuse to upgrade to a new larger tank. I think the putty approach will only be a temporary patch and is likely to only slow the leak. Personally I would continue to use the shut off valve and save for a new tank and covert the present tank to a nice quarantine tank after the repairs are done properly with the area totally dry.

I agree it'd be a bandaid at best, a mess at worst. I do think it would work for a while though (after all that's the kind of job aquamend is actually intended for).

my concern would be during power failure, you'd eventually flood your house..

 

[tigerdragon]

How low does it go level in tank with pumps off will drop to bottom of teeth and with your returns below the surface it will continue to siphon.

 

[beaslbob]

you could try letting it drop and using storage containers to catch the "extra". Where it stops draining would be the lowest spot of the "crack" in the overflow box. just a thought

 

[beaslbob]

can't you also raise the drain so the drain not the teeth stops the overflow?

 

[krisjoseph]

Hi all,

With the pumps off the water will drop to the level of the durso drainpipe, and then stop. I can raise the drainpipe about an inch or so but then it will start to bump up against the euro bracing on the edge of the tank.

I stopped in to my LFS today to grab some test kit refills and told them about the leak -- they built the tank for me and it's only 6 months old. They're going to send someone out to patch it for me on Wed Jan 7.

 

[IronVulture]

Very nice that is awesome.

 

[beaslbob]

Hi all,

With the pumps off the water will drop to the level of the durso drainpipe, and then stop. I can raise the drainpipe about an inch or so but then it will start to bump up against the euro bracing on the edge of the tank.

I stopped in to my LFS today to grab some test kit refills and told them about the leak -- they built the tank for me and it's only 6 months old. They're going to send someone out to patch it for me on Wed Jan 7.

Sound like you have an exit strategy. A few design changes and you should be able to raise the water level and avoid euro bracing.

 

[krisjoseph]

Just to close the loop on this -- the LFS sent a tech over who patched a small leak near the top of the overflow chamber. Took a little under an hour. Everything has been fine since!

 

[SanFernandoValleyAIOReef]

Just to close the loop on this -- the LFS sent a tech over who patched a small leak near the top of the overflow chamber. Took a little under an hour. Everything has been fine since!

What did they do to it? I have a acrylic or plastic over flow box leaking as well into the overflow area & draining down to my durso if there’s a power outage & the leak makes it real messy if I want to change my plumbing I’d assume