Pre drilled tank odd diameter hole

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Anubis220

Feeder Fish
Apr 7, 2025
1
0
1
46
Florida
I recently purchased a pre-drilled tank. I believe it was a DIY project for someone. There are two drilled holes, the bigger one is 1 inch in diameter and I found a bulkhead. The smaller hole is 1/2 inch in diameter and I can’t seem to find anything that will properly fit and seal to prevent leaking. This is my first drilled tank. I thought it would just use normal available pvc fittings. Has anyone else encountered this or have any suggestions

Thanks!
 
I don’t know what you’re trying to do with the tank. Either you can seal them using glass and silicone on the inside to cover the holes but if you’re looking to use bulkheads I’d personally drill both of the holes to a larger diameter depending on what size plumbing you’re going to use.

 
I recently purchased a pre-drilled tank. I believe it was a DIY project for someone. There are two drilled holes, the bigger one is 1 inch in diameter and I found a bulkhead. The smaller hole is 1/2 inch in diameter and I can’t seem to find anything that will properly fit and seal to prevent leaking. This is my first drilled tank. I thought it would just use normal available pvc fittings. Has anyone else encountered this or have any suggestions

Thanks!
Id guess it was for 1/4” tubing. Possibly for a float switch for auto top off or autodrip system. The 1” hole should fit 3/8” tubing. Those are awful tiny to serve much of any practical purpose. Was it a saltwater tank? I cant think of anything else but a float switch or something for dosing. They do make bulkheads that small in brass and plastic.
 
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I prefer drilled tanks, and although it may seem like simple DIY project, drilled tanks offer a myriad of filtration and othe choices simple glass boxes to not.
If I find an un-drilled tank, I usually then drill it myself, and have for the least 15 or more years (that is if its not made from tempered glass).
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I only drill out flows (to sumps), and prefer influents to be above the water line to create as much turbulence (and gas exchane) as possible .

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But I keep rheophillic species, so my needs may be different than yours.
Because the waters they come from require it.

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