ModularMarine 1200gph overflow box leaking

[Rham1281]

I finally got to the point where I could get a little water in my tank and see how my plumbing skills are. As I was filling up the overflow box to make sure it held water, it started leaking from the bulkhead on the external box.
I've tried what feels like everything to get this thing to hold water but nothing is working.
It came with 4 o-rings. I've got one set installed on the flange on the inside of the tank.
I've tried the second set installed between the external box and the glass, in the inside of the external box between the nut and the box, and I've even left them out all together.
I put some plumbing tape on the threads to see if that would help, but nothing works. I'm open to any ideas or advice you can give me!

 

[Sebastiancrab]

Others can chime in but I had the same problem and as best I remember I put some silicone around the parts.

 

[Saltyreef]

I finally got to the point where I could get a little water in my tank and see how my plumbing skills are. As I was filling up the overflow box to make sure it held water, it started leaking from the bulkhead on the external box.
I've tried what feels like everything to get this thing to hold water but nothing is working.
It came with 4 o-rings. I've got one set installed on the flange on the inside of the tank.
I've tried the second set installed between the external box and the glass, in the inside of the external box between the nut and the box, and I've even left them out all together.
I put some plumbing tape on the threads to see if that would help, but nothing works. I'm open to any ideas or advice you

Either your holes are too big for the bulkhead gasket or theres a ridge on your gasket not allowing the flange to sit flush against the glass or acrylic box.

You should have it going like this with two bulkhead gaskets on each bulkhead one sealing the water inside the tank and one sealing the water inside the external box.

Bulkhead flange, gasket, tank, external box, gasket, nut.

Try some new bulkhead gaskets if all else fails

 

[Rham1281]

Either your holes are too big for the bulkhead gasket or theres a ridge on your gasket not allowing the flange to sit flush against the glass or acrylic box.

You should have it going like this with two bulkhead gaskets on each bulkhead one sealing the water inside the tank and one sealing the water inside the external box.

Bulkhead flange, gasket, tank, external box, gasket, nut.

Try some new bulkhead gaskets if all else fails

So no gaskets should be on the outside of the glass?
They one set is inside the external box and the other inside the tank?

 

[Saltyreef]

So no gaskets should be on the outside of the glass?
They one set is inside the external box and the other inside the tank?

Correct. Properly installed bulkheads just need to be sealed on the side with water.

 

[Rham1281]

Correct. Properly installed bulkheads just need to be sealed on the side with water.

So I should probably seek out some new gaskets then.

 

[Rham1281]

Others can chime in but I had the same problem and as best I remember I put some silicone around the parts.

Would the silicone stick to the parts?
They're all acrylic, aren't they?

 

[Saltyreef]

Would the silicone stick to the parts?
They're all acrylic, aren't they?

Silicone sealant could help but honestly just a bandaid versus correcting the problem.

Fwiw i had this issue with some gaskets that had a ridge molded into them.
I think it was meant to act as a friction ring but for some reason it never sealed flat.

Try to clean around the holes and make sure the gaskets are dry but not dried out.
I like to lube all rubber parts up with molykote 111 and wipe off excess so it coats the rubber but not slick when tightening or it might extrude the rubber.

Mind posting up a photo of your tanks holes and the gasket size in relation?

 

[Rham1281]

I finally got to the point where I could get a little water in my tank and see how my plumbing skills are. As I was filling up the overflow box to make sure it held water, it started leaking from the bulkhead on the external box.
I've tried what feels like everything to get this thing to hold water but nothing is working.
It came with 4 o-rings. I've got one set installed on the flange on the inside of the tank.
I've tried the second set installed between the external box and the glass, in the inside of the external box between the nut and the box, and I've even left them out all together.
I put some plumbing tape on the threads to see if that would help, but nothing works. I'm open to any ideas or advice you can give me!

Sure thing. Ignore the mess around the hole.
I had attempted a silicone fix already and it clearly didn't work out...

 

[Rham1281]

Sure thing. Ignore the mess around the hole.
I had attempted a silicone fix already and it clearly didn't work out...

I ordered extra bullheads just to be safe, but I reread the instructions for the 1,000,000th time and realized that with my tank having a rim, I need to use the drilling template as a spacer.
Thanks for all the suggestions and help!

 

[BZOFIQ]

Correct. Properly installed bulkheads just need to be sealed on the side with water.

NOT the case here! If you're using overflow boxes it's different.

There is water on both sides of the bulkhead.

There really only needs to be a seal between back of tank and the external overflow box. That's what I have with zero leaks.

 

[BZOFIQ]

You should have it going like this with two bulkhead gaskets on each bulkhead one sealing the water inside the tank and one sealing the water inside the external box.

You can't seal from inside the external box the way you're saying it. Water will travel down the threads and leak between the box and the back of the tank - exactly the problem the OP has.

 

[Saltyreef]

NOT the case here! If you're using overflow boxes it's different.

There is water on both sides of the bulkhead.

There really only needs to be a seal between back of tank and the external overflow box. That's what I have with zero leaks.

I suggested a gasket on both sides where there is water contact.
Some overflow boxes are designed differently with how they're installed.

 

[Saltyreef]

You can't seal from inside the external box the way you're saying it. Water will travel down the threads and leak between the box and the back of the tank - exactly the problem the OP has.

Thanks but he figured it out 2 weeks ago with the use of a spacer.

 

[BZOFIQ]

Thanks but he figured it out 2 weeks ago with the use of a spacer.

I'll take late over wrong any day. Cheers.

 

[Saltyreef]

I'll take late over wrong any day. Cheers.