Leaking overflow box in corner tank - need help

[drstvk]

I hope someone can help or at least point me in the correct direction. I have a 75 gallon corner tank, now about 10 years old, with a 10-15 gallon sump beneath. There is an overflow box in the back corner that has a large white pipe in the center that acts as the overflow back to the sump. A few days ago I turned off the pump and the sump overflowed. It seems that there may be a leak at the bottom of that white stand pipe, as the tank runs fine without leaks when the pump is on. But when the pump is off, the water from the tank continues to drain out, even though the top of the overflow tube is no longer covered with water.
I suspect I will need to drain the tank and remove everything to get to that part, but that is much more than I can do at this time. Does anyone have a suggestion? I have never investigated that part of the tank, so I have no real idea how it works. Only it doesn't work correctly now.
I was hoping someone from one of the LFS could come and fix the problem, but the one store in Santa Rosa California basically told me just to buy a new tank, as they were too busy to make a service call.
Any idea if anyone in the north bay area of SF does this kind of work? Any idea how to "easily" DIY it?
Thanks for any help.
Steve

 

[Sk8r]

I'd prepare extra buckets to contain specimens if things go wrong, and empty buckets to contain water if things get out of control, but I have totally replaced tank plumbing without draining it.

First, I hope your stand is large enough and open enough you can physically get under it on your back.

If not you will have to slide the tank out to get at it. Get some of those 8" moving glides (round) sold by Lowe's. With help, lower tank water to half or less, gently rock the tank and insert glides so you can get it out far enough to let you work underneath.

You will need: new bulkhead connectors. This is assuming the leak is there. Possibly a gasket has gone. YOu may have to go to your city's plumbing supply if the lfs doesn't have some: white pvc is all you can use. My Lowes didn't even know what a bulkhead connector was. If not local, you may have to order it. Tightening a bulkhead connector: you should use no more force than a strong woman would exert, hand tightening. Over-tightening could crack your bottom glass and indeed cost you a tank. Pump or siphon your downflow box dry.

Remove the standpipe system and use new connectors. What you will see is two neat round holes ready for new connectors and attachment to hoses. Clean everything. Your new gaskets should enable you to make a good seal on well-cleaned and dry glass.

OTOH, and before doing any of the above, wrap a paper towel around the gaskets in question from below and see what's leaking: the paper towel will tell you. If it is a mere clog in the drain, removing the standpipe manually from above might tell you. I HOPE you didn't purple-glue the thing into the socket: this is never a good idea. YOu can 'snake' the line with a flexible wire to see if there's any impediment.

It's hard to tell somebody how-to on an operation this complex, but if you should have a local reef club, now would be a real good time to join. This is not hard to do, and is pretty intuitive if you have any experience at all with plumbing. The main thing you can do wrong is remove the bulkhead connector without pumping out the overflow or worst of all, overtightening the new connector and cracking your glass. To test your new connection, pour water into the downflow and see if it holds water or leaks. A new bulkhead connector can weep a tiny bit, but should not leak.

I am SURE in SF north bay there MUST be a reef club who would be happy to come help. Look in our regional club index way down at the bottom of the forums. Or your lfs may be able to tell you who to contact. Offer pizza and eternal gratitude. Most will assemble for a party.

 

[billdogg]

I want to make sure I understand. Water is no longer coming over the top of the overflow box, it is coming from one of the seams - either along one of the sides or along the bottom, correct? is it then draining into the sump from the top of the overflow tube or is it leaking where it (probably) presses into the bulkhead?

If it is leaking at the bulkhead junction, it may be as simple as pressing it back in a bit. If you want or need to repair the seams of the overflow box itself, then yes, you'll have to drain the tank. It will be a total PIA, but very doable.

From the description as I understand it, it is not the bulkhead itself that's leaking, but rather the plubing on the inside fo the overflow is not sealed properly to it.

 

[Sk8r]

Ah, Billdogg, thanks for chiming in. This is hard to advise by remote!

 

[hogfanreefer]

Are you saying water continues to run from your drain pipe in to your sump after the water level in the overflow is below the opening of the pipe? If so this is not due to the bulkhead or the overflow box but it's in the pipe or it's fitting in to the bulkhead.

For what it's worth a properly designed system should have plenty of space in the sump for all of the water in the overflow box without over flowing.

A leak in the over flow box itself will drain the entire tank if the standpipe is removed or leaking near the bottom.

 

[drstvk]

Thanks all. Hogfanreefer, that is exactly what is happening. I'm sure the leak is where the standpipe is attached at the bottom. I am positive that if the pump were to stop, all of the water in the tank would empty over time. I am the world's worst plumber, so I really hesitate to tackle even a minor leak, much less one like this. And I really have no idea if that standpipe is simply pushed into place, glued into place, or threaded into place. I've never investigated it before as it's never given me a reason to look.
Maybe someone on this forum knows someone in the north bay area who would be willing to tackle it. I've offered to pay the LFS to fix it, but they say that all there guys are busy and didn't even offer to help. There is a local guy who offers emergency help, but he has not called me back.
But if there is some trick to just getting the standpipe back into place without draining the tank, please let me know.
If I have to drain the tank, I guess my fish and corals are available to anyone in the area who wants them. The last time I drained the tank to move it, nearly everything I had died in the buckets. Keeping them warm, oxygenated, etc just didn't work for me.
Anyway, thank you all for responding.

steve

 

[Sk8r]

What brand is the tank? Oceanics and Aquavim have a double-walled downflow which cannot allow a draindown of the tank below a certain point.

 

[hogfanreefer]

If the overflow box is not leaking the tank will not drain just the overflow box. I occasionally pull my drain pipe out and drain the overflow (usually to flush out a snail stuck in the pipe).

Can you re-route your drain to a bucket and turn the pump off. If the water all drains out of the box and it doesn't start to refill the box, the box itself is not leaking just the stand pipe. Removing and cleaning the joint part of the pipe and then replacing might fix it if that's the problem.

During normal operation a small leak there is no problem. It's also not a problem with the pump off if your sump has enough capacity to hold all the overflow contents. Good luck, let us know what you find.

 

[drstvk]

I don't know what brand it is. Someone else bought it. It doesn't have any brands on it I can find. The overflow box has small slits at the top and at the bottom. I was trying to figure out how water was getting into the box once the level dropped below the top set of slots, but it seems that there are slots at the bottom, too. I am guessing that the standpipe, which has a small hole in it near the top is what keeps the water level where it's supposed to be when the pump is off. Now that the standpipe isn't secured (or whatever it's supposed to be), water leaks out the bottom. Is that standpipe typically glued or threaded in place? Siliconed? Or just locked tightly by friction? As I said, I've never investigated it before. If I pulled it out while the pump is running to clean it, would the entire tank just empty onto my floor?

 

[Sk8r]

Get up on a stepstool and look down at the overflow box. Does it have a double wall? If it does, if, for instance, you can put something like thick paper down between the walls (don't let it go!) it is an anti-draindown protection. The internal wall will be solid, without holes, all the way to the bottom, and the top of the inner wall will act as a waterfall, below which level water cannot drain unless the overflow itself is unglued. See if you or a person with very small hands can reach in all the way to the bottom and confirm that it is a solid piece with no holes. If it is solid you should be safe to pull the standpipe.

The standpipe should be loose. You should be able to pull it out bytwisting it slightly. If not, don't force it.

 

[hogfanreefer]

I've seen that type of overflow (our LFS has tanks with it). The ones I've seen were double walled as Sk8r is describing. If so the inner wall is solid and you should be able to pull the standpipe without draining the tank. I can't imagine a reason for having holes/teeth at both the bottom and top without the double wall construction.

 

[drstvk]

Oh Yes!! It is a double wall construction. Water runs from the outer part over a waterfall into the Overflow. So do I just drain down enough water from the tank so the overflow will fill the sump, then pull the standpipe out? Is the standpipe just sitting in the fitting at the bottom or is it supposed to be glued, siliconed, etc. Or is it threaded?
And thanks for all the assistance. I feel like a numbskull when it comes to plumbing. I'll take electrical work any day: it either works, doesn't work, or kills you. There is never any "leaking".

Steve

 

[JMorris271]

I just had this problem with a tank. The seal between my overflow box and the tank were not soundly sealed I had to drain it, tear the overflow off ,clean the silicone off the tank and the overflow. I put new bulkheads in just for the heck of it and then resealed the overflow to the tank.Works fine now and no leaks. the bulkhead can be either way, depending on the type of bulkhead was installed.To tighten it up the standpipe, wrap silicone tape around the pipe a few time to snug it up.

 

[drstvk]

Thank you all for the great assistance. I drained about 5 gallons out of the tank to get the level a good 2" below the slots in the overflow, pulled and cleaned the standpipe and just put it back, screwing it in tightly (it is just a PVC slip fitting), redirected the inflow pipe, and now it's acting completely normally. It did seem like the inflow was acting a bit like a siphon when I inadvertently bent it down, but it stopped once I put it back in the right position. Is this common?
Anyway, cleaned the tank, checked the chemistry (after all this hassle with plumbing, the chemistry is still perfect - amazingly) and put all the parts back together. My skimmer had gotten noisy, but now that it's cleaned and put back together, it's back to silence again. Replaced phosphate binder and charcoal in their respective places, did a 10% water change, and now all is good with the world.
Amazing how crappy it felt when all I was worried about was how to keep these critters alive and happy. I've got a school of Damsels that are a pain in the neck much of the time, but I do love their antics. I just wish one of them would stop trying to eat my big old crab.
Anyway, a giant thank you to all of you who answered my plea for help. I've been lurking and reading here for the last 6 months, but I guess I'll have to become more active after all you guys have done to help me.

Steve

 

[ska d]

i may not understand your overflow completely but, just to be safe. you are sure after you shut the return pump off the water was was still draining from the overflow and not the return. i just cant picture it in my head. if no water is being returned from the sump then a leak in the overflow should only drain whats left in the overflow box itself. otherwise why wouldnt it just keep draining even without a leak when the return pump is off. typically when a sump overflows its because the return doesnt have a syphon break or its blocked. or if a check valve is used it has failed. which is why the return shouldnt be placed to low in the display tank to avoid half the tank draining into the sump. i may not be familiar with your type of overflow, so i may be missing something. but i just want to make sure you have covered all your bases. so to be sure, your return has a hole in it somewhere just under the water line, and or you have a check valve installed, and the return isnt to low in your display.