# plugging up bulkheads



## Rain_Frog (Apr 27, 2004)

Okay, I may be getting a bunch of used tanks from someone. They all have holes drilled in the bottom for bulkheads. 

What do you recommend to seal up a hole at the bottom of the tank? I would still like to have the option of removing the seal if I wish to, but for my current projects, sumps for these tanks would not be needed.

The only thing I can think of is to buy 4" x 4" pieces of 3/16" glass and silicone them to the bottom of the tank. Therefore, I could always use a knife to remove them.

Is there another way that doesn't involve silicone? I think it'd be kinda cool to leave a bulkhead in there with a pipe coming up from the substrate to increase air flow, but that would require me to invert a bulkhead, something I don't know would be safe in case of leaks.


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## JoshH (Feb 13, 2008)

If the bulkhead is still in place, you can get a PVC plug to screw into the hole. If it is just a hole in the glass, either buy a bulkhead/plug or use a small piece of plexiglass and silicone it down. Plexiglass will be easy to pry up later if neccessary, while glass would break.


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## pl259 (Feb 27, 2006)

Rain_Frog said:


> ...The only thing I can think of is to buy 4" x 4" pieces of 3/16" glass and silicone them to the bottom of the tank. Therefore, I could always use a knife to remove them.


The glass patch is on the inside of the tank right? That's the approach I've seen and heard most often. Make sure to use a good aquarium grade silicone.


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## RecycledAgain (Oct 26, 2008)

I have used bulk head fittings for the last 20 yrs in car wash applications and I use them on a few tanks. I don't believe I have ever had one fail or leak that I can think of. If you do invert it , just make sure the rubber gasket is clean and flexible and you shouldn't have any problems at all, especially since the rubber seal will be hid from sunlight.

Dan


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## jubjub47 (Sep 9, 2008)

Put bulkheads in backwards from usual, but put the rubber gasket on the inside still. you can then plug the bulkhead with a threaded male cap on the inside and you shouldn't have any problems with the bulkhead being lower than the tank trim. Simple way to do it and removable by hand with not tools necessary.


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## Jason DeSantis (Feb 2, 2006)

If you dont plan on using the hole in the future the best way to plug it is a 1/4" thick piece of plexi glass and some aquarium silicone. Works great everytime and if you ever wanted to use it again you could just drill the plexi or remove it.
J


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## insularexotics (May 3, 2005)

jubjub47 said:


> Put bulkheads in backwards from usual, but put the rubber gasket on the inside still. you can then plug the bulkhead with a threaded male cap on the inside and you shouldn't have any problems with the bulkhead being lower than the tank trim. Simple way to do it and removable by hand with not tools necessary.



Hi Tim!
In my experience, putting the gasket on the same side as the nut is a recipe for leaks. The gasket is not designed to seal the threads on the outside of the bulkhead fitting. It is designed to make a seal between the flange of the bulkhead and the tank.

Doug,
To seal the hole reversably, why not put the bulkhead in normally and put a valve on the outside? Then you can always open it as a drain or to connect it to a sump. Or you can put the bulkhead on normally and put a plug in if it is threaded, as others have mentioned. If it is a slip bulkhead, just glue a piece of pipe into the bulkhead and glue a cap onto the pipe. Just be sure to leave enough pipe to be able to cut off the cap and still be able to glue a valve or some other fitting onto the pipe. If you really don't want a bulkhead protruding from the bottom, your best bet is to silicone a piece of glass over the hole from the inside. You can cut it off later without breaking the glass (done it myself). And silicone does not stick to acrylic as well as it does to glass.

Just some aquaristic thoughts.
Rich


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## jubjub47 (Sep 9, 2008)

insularexotics said:


> Hi Tim!
> In my experience, putting the gasket on the same side as the nut is a recipe for leaks. The gasket is not designed to seal the threads on the outside of the bulkhead fitting. It is designed to make a seal between the flange of the bulkhead and the tank.
> 
> Doug,
> ...


Hey Rich, as long as the bulkhead is hand tight you will have no problems with the gasket not holding in a frog tank. If he was setting up an aquarium I would advise against it, but there is not enough pressure to be a problem on a tank with just a few inches of water. Also reversing the bulkhead will allow him to setup the tank on a flat surface instead of having to elevate it to clear plumbing from the bulkhead and valving.


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