Modular Marine Overflow leaking

[BZOFIQ]

Interested to see how this plays out.

 

[ReefWithCare]

This is how it is designed. Any water getting through the bulkhead will simply make it back to the overflow box since the box is sealed to the tank.

That being said, I think it can and should be improved. The issue with this design is that water will slowly trickle through to the overflow box until the water level in the DT gets below the bottom of the drilled holes....for some people that could be a disaster if it is left not running for a day or more due to a power outage. I would much rather know that the bulkhead is sealed at the tank.

When I install mine this week I am going to put a sheet gasket between the tank and the overflow box, and use the bulkhead gaskets inside the tank. To me, this will give a much better seal, as it will support the overflow box at all points instead of letting it hang a little with just a round gasket between it and the tank. For $9 on amazon, I got a 12"x20" sheet of 1/16" rubber gasket material, and will simply cut it to the size of the overflow box, and cut out the circles for the bulkheads to slide through.

Mine drops water inside the overflow box and this would cause a problem in the event of a power outage. My sump can hold the water if it drained - but I would prefer no leaks whatsoever

 

[ca1ore]

The tank is painted in the back. That could be why it’s leaking because all the other bulkheads do not leak with the gasket on the inside of the tank.

The hole looks good, very good actually . You may want to try removing the paint from underneath the gasket to improve the seal. Even using a gasket inside the tank under the flange will not fix this because water can still get to the gasket on the outside of the tank via the threads. The reason a standard installation bulkhead works with a single gasket under the flange is that there is water only on one side - here it's on both sides.

 

[ca1ore]

That being said, I think it can and should be improved. The issue with this design is that water will slowly trickle through to the overflow box until the water level in the DT gets below the bottom of the drilled holes....for some people that could be a disaster if it is left not running for a day or more due to a power outage. I would much rather know that the bulkhead is sealed at the tank.

The more fundamental 'issue' is the removable skim box. Since that is not completely water tight, even with a gasket under the inside flange, there is still the potential for the drain down as you describe (thus the internal gasket being unnecessary). It's a trade off. When I bought my MM I opted to NOT get the removable skim box for precisely this reason. BTW, I say 'potential' because the reality is that the seeping would be so slow that it would become a problem only with a really protracted power loss.

 

[Fin]

Install the two gaskets you ordered and if it doesn’t fix your problem, contact the overflow manufacturer. I am betting it takes care of your issue.

 

[ReefWithCare]

Install the two gaskets you ordered and if it doesn’t fix your problem, contact the overflow manufacturer. I am betting it takes care of your issue.

I contacted him - I will likely have the gaskets installed before I hear back from him.

I have another guy I talk to went and install a giant gasket around the box for his 300g tank and is going to put the normal gasket on the inside. Hopefully he doesn’t leak as well [emoji53]

 

[Caravanshaka]

I contacted him - I will likely have the gaskets installed before I hear back from him.

I have another guy I talk to went and install a giant gasket around the box for his 300g tank and is going to put the normal gasket on the inside. Hopefully he doesn’t leak as well [emoji53]

that is me on facebook

 

[ReefWithCare]

that is me on facebook

Lol. I’ve been doxed [emoji28]

 

[roberthu526]

I think I placed the gaskets between the tank glass and the out box. I think that was what suggested by modular marine.

 

[ReefWithCare]

I think I placed the gaskets between the tank glass and the out box. I think that was what suggested by modular marine.

It is. It is so against everything we know about bulkheads lol. I still have a leak doing it the "wrong" way :mad:

 

[ether]

OP, as several people have stated, the gasket does not go inside the tank, it goes between the tank and the overflow box. I have one set up like that, my tank is painted, never any issues. If you put it inside the tank, it will leak.

 

[ilyad]

I dont have this brand, but I have the Eshopps one that works very similarly, where the gasket goes between the tank and overflow box. My tank also had some small chipping when drilled and its painted in the back, yet I still have no issues with any leaking, so the design definitely works.

That being said, I had two problems with mine that was causing a slowly leak until fixed. 1. All of the plumbing was heavy and causing the the bottom of the overflow to be pulled "toward the tank" which in effect created a small gap on the top half of the bulkhead, causing a slow drip. Adding a spacer on the plumbing allowed it and the overflow to sit evenly. 2. Over tightening the bulkhead. Believe it or not, if you tighten in too hard, it skews the rubber gasket, causing it to have small gaps through which water will seep.

So make sure there is no pressure from the plumbing causing the overflow box to skew and try loosening the bulkhead nut just a tad to see if the rubber may seat better.

 

[WVNed]

So you put it together wrong and it leaks.

Hmmmmm.

 

[ca1ore]

One 'trick' that I did with mine that helps is to stick a strip of gasket material along the bottom edge of the face of the external box that sits against the back of the tank. The is gasket material should be of the same thickness as the bulkhead gaskets and prevents the external box from torquing downwards.

 

[Zwogle]

I had the same problem, I think the key was like others have said to place the gasket between the external box, and the tank. That being said I ended up using 4 gaskets...

 

[TaylorPilot]

Right, the only CRITICAL place for a gasket is between the tank and external box. So, if your overflow has two bulkheads that connect the internal skim box to the external plumbing box then the two gaskets go on the bulkhead stubs where they protrude out of the back of the tank.

This is partially correct in that it won't leak out on to the floor, but without the internal gaskets, the water can travel down the bulkhead threads into the rear box. What happens is if there is a power outage, the water in the main display will slowly leak down to the bottom of the bulkheads. That is typically 4-5" depending on the manufacturer's design. I haven't looked at modular marines, but unless they some how seal the internal box to the glass, you need two sets of gaskets. One on the inside to prevent leak down during power outage, and a second set on the outside to keep the water from dripping.

 

[TaylorPilot]

Well I just looked at the design, and unless those slip fittings going into the bulkheads are water tight, the internal gaskets won't fix the problem because the water will slowly leak through the bulkheads. I would suggest making sure your sump can handle the excess water in the event of a prolonged power outage, because the tank will eventually leak down several inches if the power remains off for an extended amount of time.

Like others have said though, also make sure that you aren't putting any torque stress on the box from hanging plumbing. I like to use the metal pipe brackets that use 3/8" threaded rod from Lowes. You can adjust them to where they hold it perfectly straight.

 

[ReefWithCare]

I had the same problem, I think the key was like others have said to place the gasket between the external box, and the tank. That being said I ended up using 4 gaskets...

Was one set in the inside and the other set on the outside?

MM is telling me to to use 2 sets of gaskets on the same side [emoji848]

 

[Caravanshaka]

Was one set in the inside and the other set on the outside?

MM is telling me to to use 2 sets of gaskets on the same side [emoji848]

If you have 2 gaskets, they go between the tank and overflow. If you now have 4 gaskets, you want the bulkhead to tank sealed and then tank to overflow.

 

[Nano40]

I just fixed my slow leak MM overflow by installing the provided gasket in the tank and getting a 2nd set from Amazon for between the the box and the tank....no more leak...honestly without the gasket between the tank and the box there is no way to stop the water from seeping between plastic and glass..