Leaking overflow box....stumped.

[Jakepen]

Hey guys, I have the modular marine on my 180. When water in the overflow box reaches the top water will leak out of the bulkhead, and drips down the back of the tank. Emailed modular, they said clean the back of the tank and the gasket, I did that. Before I did that it leaked wherever the water level was, so it was a improvement anyways. At this point I’m not sure what to do. The only gaskets provided are placed between the outside of the tank, and the outside of the overflow box. My thought is it could possibly be from a sloppy drill job, and the chips in the glass are stopping the gasket from getting a good seal. Modular marine told me to go to my auto store, and get gasket sheet (see pictures, not sure how reef safe it is), cut it and leave extra on the outer diamet to possibly fill in the chips. A member suggested running a bead of silicon on the gasket to create a good seal. I was thinking maybe add another gasket to the inside of the overflow box, between the wall and the nut. There seems to be a gap between the nut and the wall, only place I can fit my fingernail, and that’s where the water level is at when it begins to leak. Any thoughts, or suggestions are appreciated. (I have posted about this previously and it is being talked about in another thread of mine, however this is the last step before pushing my tank against the wall and starting the cycle).....

 

[redfishbluefish]

First off a gasket on the nut side does nothing....the water follows the threads.

Just to make sure, you should have a gasket on the flange of the bulkhead and a second gasket between the tank and the overflow. Also make sure the nut is tight enough....hand tight and than a 1/4 turn.

 

[brandolphjr]

I would use a thin bead of silicone around both sides of gasket,,and let it fully dry... plumbing trick I use at work,,that works great..[emoji3]

 

[ca1ore]

You painted the back of the tank, right? Did you paint right up to the bulkhead holes, or did you leave a ring of clean glass? I have found that gaskets don't always seal well against a painted surface. FWIW, the newer MM overflows required a gasket only between the back of the tank and the external box. Running silicone sealant on both sides of the gaskets will certainly do the trick - problem is you then have to let it cure for a few days, maybe even a week.

 

[Jakepen]

First off a gasket on the nut side does nothing....the water follows the threads.

Just to make sure, you should have a gasket on the flange of the bulkhead and a second gasket between the tank and the overflow. Also make sure the nut is tight enough....hand tight and than a 1/4 turn.

It’s not required apparently on modular marine overflows to have a gasket on the flange, thought it was strange myself, so I used one anyways.

I would use a thin bead of silicone around both sides of gasket,,and let it fully dry... plumbing trick I use at work,,that works great..[emoji3]

That’s what another very helpful member recommended, I’ve read that it’s not advised though? Also would I want to put it on both sides? Not sure how silicon is when it cures, but will I be unable to remove the overflow box after it cures?

 

[Jakepen]

You painted the back of the tank, right? Did you paint right up to the bulkhead holes, or did you leave a ring of clean glass? I have found that gaskets don't always seal well against a painted surface. FWIW, the newer MM overflows required a gasket only between the back of the tank and the external box. Running silicone sealant on both sides of the gaskets will certainly do the trick - problem is you then have to let it cure for a few days, maybe even a week.

The back is painted, I did clear a large surface for the gasket. Letting it cure for a week isn’t a big deal, this build is going on about 9 months now haha.

 

[brandolphjr]

It’s not required apparently on modular marine overflows to have a gasket on the flange, thought it was strange myself, so I used one anyways.




That’s what another very helpful member recommended, I’ve read that it’s not advised though? Also would I want to put it on both sides? Not sure how silicon is when it cures, but will I be unable to remove the overflow box after it cures?

Silicone is great leak prevention and stopper,,and can be removed by acetone..I always coat both sides of gaskets,,it side's in place better on the threads..[emoji3]

 

[Fin]

On other Ghost style overflows, there are two gaskets, like @redfishbluefish mentioned. I think you are the second person this weekend I have seen posting about these overflows leaking. I would get two more gaskets and use one in between the back side of the inside box and the inside of wall of the tank. The other would go between the outside of the tank and the outside box of the overflow. Like this....




Also, silicone should not be necessary on gaskets.

 

[Jakepen]

On other Ghost style overflows, there are two gaskets, like @redfishbluefish mentioned. I think you are the second person this weekend I have seen posting about these overflows leaking. I would get two more gaskets and use one in between the back side of the inside box and the inside of wall of the tank. The other would go between the outside of the tank and the outside box of the overflow. Like this....




Also, silicone should not be necessary on gaskets.

I did get two more gaskets and did just that, to be sure. Still a slight leak when the water reaches that certain point. Will the chips taken out when drilling the tank have any effect on the seal?

 

[brandolphjr]

That's why I use silicone.

 

[rc1626]

I did get two more gaskets and did just that, to be sure. Still a slight leak when the water reaches that certain point. Will the chips taken out when drilling the tank have any effect on the seal?

Depends on the size of the chips. Slight bit of silicone on the gasket that sits outside the tank and a little silicone on the threads as well. Have done it this way a few times with zero leaks. As stated, if you fear chips in cut out are causing the leak then a little silicone on inside gasket as well.

 

[brandolphjr]

You got think about a themostat in a car...There is a gasket and silicone on both side to prevent leaks at high temp and pressure..You don't need a whole lot , just a little on your finger to coat the gasket, a real thin layer.

 

[Jakepen]

Is applying silicon a potential leak point down the road, is it just a band aid?

 

[Jakepen]

Also what if I do silicone both sides, put the box back on, let it cure and it still leaks? Also should i silicone the gasket that is inside of my tank?

 

[Fin]

How big are the chips?

Is applying silicon a potential leak point down the road, is it just a band aid?

IMHO, yes - potentially. Bulkheads are not meant to be installed that way. Silicone does not adhere to rubber gaskets long term. Jerry-rigging may work, but if it were mine, I would want to know what is causing it to not seal and fix it correctly. That's just me and my 2¢ though.

 

[ca1ore]

Since you don't appear to be in a hurry, I'd try to figure out why it's leaking. These things aren't really complicated. Maybe the external box has a slight twist to it, or perhaps the bulkhead has a damaged thread since you can get a fingernail under one part of it. BTW, if you end up using silicone, you don't actually need the gasket. Once the silicone cures, it functions essentially as the gasket.

 

[Jakepen]

I agree with you both, I definitely want to know why it’s leaking rather than putting a bandaid on it. Any suggestions what I should check when I get home then?

 

[Jakepen]

So I took everything off to get a look at the glass again, and this is the side that leaks. One picture of the side that does not leak...
I’m pretty sure this is the problem, so what do I do?

 

[Jakepen]

Anyone? I don’t mean to be so impatient, but this is the last thing that has to be done before I can push the tank back and get the cycle started...

 

[ontop27]

Is it possible that you over tightened? I have done pretty bad drill jobs and they didnt leak. I would take it off and reinstall and see what happens. I had this is issue before