Smallest Bulkhead?

Rjukan · Feb 3, 2024

Hi all,

I used to have this little 7.5 gallon nano AIO plumbed into my system but I ran into a slow leak around one of the the drain pipes, which caused all sorts of salt creep and intermittent flooding down my wall. The previous owner did the drilling and the connections, and I didn't realize how bad it was until today when I took it apart.

My question is, are there any bulkheads this small? The opening is spot on 5/8" I would rather not do it the way the previous owner did with crazy glue and silicone, but that might be the only option? Any suggestions are greatly appreciated!

The other pipe is the emergency overflow and it seems very tight, but if I can find a good option to replace the other one, I'll change that one too.

Quietman · Feb 3, 2024

You might find a uniseal to fit - but you'd only be looking at 1/4" pipe when done. Doubt that'll work for anything. Might be able to make your own 'bulkhead' with a threaded 1/2" pvc and two pvc nuts to tighten down on either side of glass and then you could just cut out some seals from silicon mat. If no DIY, then for any useable pipe size (1/2") you're looking at some kind of liquid gasket sealant.

Harpo · Feb 3, 2024

Could the hole be enlarged? You would need a 30mm hole for the smallest BRS bulkhead

Kfactor · Feb 3, 2024

1/2' elbow with thread one side with a thread in insert with gasket

Rjukan · Feb 3, 2024

Quietman said:
You might find a uniseal to fit - but you'd only be looking at 1/4" pipe when done. Doubt that'll work for anything. Might be able to make your own 'bulkhead' with a threaded 1/2" pvc and two pvc nuts to tighten down on either side of glass and then you could just cut out some seals from silicon mat. If no DIY, then for any useable pipe size (1/2") you're looking at some kind of liquid gasket sealant.

Yeah 1/4" wouldn't cut it I think.. but the threaded, with 2 pvc nuts and diy gaskets sounds like its possible. What kind of liquid gasket sealant could I use?

Harpo said:
Could the hole be enlarged? You would need a 30mm hole for the smallest BRS bulkhead

Unfortunately there isn't much room between the edge of the opening and the tank corner, or the other pipe.

Kfactor said:
1/2' elbow with thread one side with a thread in insert with gasket

Sounds similar to the other suggestion, and I think you both are on to something. I'll take a ride to the hardware store later and see what kind of pvc and fittings they have. I'll probably end up having to order them though.

Quietman · Feb 3, 2024

I'd start with aquarium glass silcone sealant. It won't bind to pvc well but it will to glass very well.

You could also search on other AIO tanks and see if there are any replacement parts you could order that would work on your tank. Long shot.

MoshJosh · Feb 3, 2024

Rjukan · Feb 3, 2024

MoshJosh said:

That was extremely helpful. Thanks so much!

Rjukan · Feb 3, 2024

Finding anything that has a 5/8" outer diameter is a real challenge. I don't want to even waste my time going to Lowes or HD, I doubt they will have anything that small.

I've searched online but haven't found anything so far.

MoshJosh · Feb 3, 2024

Rjukan said:
Finding anything that has a 5/8" outer diameter is a real challenge. I don't want to even waste my time going to Lowes or HD, I doubt they will have anything that small.

I've searched online but haven't found anything so far.

HD has some odd sizes in the irrigation and toilet plumbing sections. I have used sink gaskets and garden hose gaskets with success in the past.

I have to go to HD later today so I will keep an eye out.

cilyjr · Feb 3, 2024

Drilling it larger is easy enough, if you've got the room.

If not using conduit adapters is your next best option. As they are not npt they will thread to flush. The issue with that is there is no fitting that has a large flange on it. It will have to be very close to the proper hole size.

I didn't watch it but I believe that's what the kid in the video is doing.

Rjukan · Feb 3, 2024

I've thought of drilling 1 larger hole that covers the 2 of them. I didn't like the siphon drain bc it was too hard to keep the return dialed in at the right pressure.. I'm remembering now that the siphon would start going and pull too much water out of that compartment which would make a loud sucking sound, then the siphon would break. The chamber would refill, start going out the emergency drain until the siphon would start again, at which point the process would start over.

cilyjr · Feb 3, 2024

Rjukan said:
I've thought of drilling 1 larger hole that covers the 2 of them. I didn't like the siphon drain bc it was too hard to keep the return dialed in at the right pressure.. I'm remembering now that the siphon would start going and pull too much water out of that compartment which would make a loud sucking sound, then the siphon would break. The chamber would refill, start going out the emergency drain until the siphon would start again, at which point the process would start over.

Did you put a gate valve on the siphon to control it?

Rjukan · Feb 3, 2024

I did have a gate valve, but even the high quality one I had didn't help dialing it in. It's been a few years now since I had it hooked up, but I'm wondering now if I had it on the return line, or the siphon.

*edit: Yeah it was definitely on the drain line.. I saved the plumbing and just checked it

Reign1 · Feb 3, 2024

Uniseal or diy bulkhead w/ male/female and gasket as poster said ..
that’s what I would do

Rjukan · Feb 4, 2024

Ok I've found 1 piece of the puzzle, PEX pipe comes in the perfect diameter for those holes, and the inner diameter is noticeably bigger than what was on there. There are all sorts of fittings for them, and I found that the 1/2" pvc couplings fit perfectly over them as well. So I'll be able to attach the return to my pump easily.

Now I need to decide how to deal with the bulkhead area. I'm thinking about gorilla glue on the outside, and a nice bead of silicone on the inside. Any better ideas? Thanks!

Rjukan · Feb 17, 2024

Update!
My plan didn't work. Not even close. Soo, I ended up widening the holes after not finding anything less than 3/8". It went pretty well..

2nd hole was easier lol

Much bigger than what was there. Rubber O rings on the inside and female couplings on the outside. I'll cap them for leak test!

Rjukan · Feb 17, 2024

Quietman said:
You might find a uniseal to fit - but you'd only be looking at 1/4" pipe when done. Doubt that'll work for anything. Might be able to make your own 'bulkhead' with a threaded 1/2" pvc and two pvc nuts to tighten down on either side of glass and then you could just cut out some seals from silicon mat. If no DIY, then for any useable pipe size (1/2") you're looking at some kind of liquid gasket sealant.

This is pretty much what I did. Thanks for the suggestion!