Plugging a hole in the bottom glass?

[Andy V]

What is the best way to go about plugging a hole in the bottom of a tank? I came across a tank I want to buy, but it is drilled in the bottom (two holes) and does not have an overflow. It was used for a trade show, so the overflow was not a concern for the owner since they just had pipes in the open, but this will be my display tank.

I was going to use a glass-holes overflow...I'd rather not try to use the current holes for drains. So I have a some options:

1. Do the glass-holes overflow and plug the two existing holes. It seems the best way to do this is to install bulkheads that are threaded, and then plug with threaded end caps that are glued on. Seems fine but I am afraid that it could leak longer term, and since it's not in an overflow, the entire tank could drain.

2. Run a pipe to these two holes and put a return pump for extra flow. This options complicates the entire setup and still has the potential for the entire tank to drain. It's not that appealing to me.

3. Actually install an overflow using these corner holes. The problem with this is that the holes are far away from the edge, which means the overflow would take up a ton of display space, plus the tank is a custom tank from one of the best custom manufacturers there is...my silicone job would likely destroy the look of the tank.

So am I overly concerned by a plugged bulkhead leaking>? Tons of people used to do closed-loops without many problems it seems. How often do bulkheads leak? I am pretty sure if it started to leak, I'd have to drain the entire tank, correct?

Thanks for the help in advance.

 

[Kungfukid]

I do not think glass-holes overflow box works for bottom drilled holes.

you could use one of the holes (with a pipe) for a return and plug the other one.

 

[mnavick]

I do not think glass-holes overflow box works for bottom drilled holes.

you could use one of the holes (with a pipe) for a return and plug the other one.

Think he meant install the glass-holes and take those cut out pieces of glass and re-use them to plug the existing ones.

I would go with a bulkhead and cap or extra flow method. Just do a fresh water test before setting up .

 

[Andy V]

Yes, I meant using the gh overflow and plugging the two existing holes.

 

[smithcreek]

I think you could just silicone a piece of glass over the holes on the inside of the tank. I have a closed loop with 6 holes in the bottom of my tank, running for 5 years with no problems, but leaking is always a concern. With all the propeller pump options with wavemakers and fancy electronics I wouldn't recommend a closed loop to anyone. I mainly use tunzes and only run the closed loop 6 hours a day.

 

[jayman10134]

I would cut squares so they overlap at least 2 inches over, probably 1/4" to 1/2" and just silicone them shut. I had a 150 crack across the bottom front to back and just silicones a 1/4" piece of glass over it and it has been leak free for years.

 

[Kungfukid]

I think bulkhead with cap would do.

 

[Old Glory]

I would cover with glass/acrylic sealed with silicone on the inside inside and let it dry. Would then fill in the circle on the outside/bottom with silicone and cover/seal with glass/acrylic.

 

[Andy V]

If I were to use the glass over the hole method, do you put silicone between the pieces of glass and on the edge, or just on the edge?

 

[JohnK]

I'd apply silicone between the glass and the glass patch. Definately use glass, acrylic doesn't bond with glass properly for something like this.

Also allow extra time for it to cure, like 2 weeks (the silicone inside the sandwich will take longer to fully cure)

 

[Andy V]

I would cover with glass/acrylic sealed with silicone on the inside inside and let it dry. Would then fill in the circle on the outside/bottom with silicone and cover/seal with glass/acrylic.

Can't do the underside since it's a frameless tank, but I can do the inside no problem.

 

[JohnK]

That'll work just fine. Clean the glass with aceytone before applying the patch.

 

[Andy V]

Should I be nervous about this at all? It's kind of freaking me out!

 

[Andy V]

So I am going with the glass patch. I have some of the DAP aquarium safe silicone. I assume this is fine?