Can I use plexi glass to repair a glass tank with a small crack on the bottom?

[squeegee_gal77]

I have a 45 gallon corner tank that is drilled for a sump system. We have spent quite some time putting this thing together and now there seems to be a crack between the two holes in the tank. There was a slight chip in one of the holes prior to installing the bulkheads, and I'm assuming my hubby may have accidentally over tightened the bulkhead and that chip spread, or maybe when I added cold water to test the new pump....
ANYWAYS....
The crack is maybe 1.5"-2" long. I have aquarium silicone and a (approximately) 3"x20" piece of plexiglass. Could I smother the two surfaces with silicone and cover the crack with the plexiglass (which we would then also drill through and reinstall the bulkheads.
Terrible idea? Anyone ever done a repair like this? I've seen repairs done like this with glass on glass, but....?
Any advice is appreciated?


Sent from my iPhone using Aquarium Advice

 

[Mebbid]

Imho, the bottom really needs to be replaced on a tank like that. There is going to be over 400 lbs pushing against that bottom pane of glass and and damage to it is asking for disaster.

 

[BillD]

You can't trust the plexiglas to adhere well enough to offer true support, the way you would if the patch were made of glass. Silicone just doesn't stick to acrylic all that well.
There are ways of repairing this without replacing the bottom, if that is where the crack is.
In my view, a repaired bottom needs to be supported, which negates the down forces, and then a simple patch will normally suffice. In this particular case it would seem the crack will run from one hole to the other at worst and then stop. A patch that covered both holes would likely do the job, although, without seeing it, it is just speculation.

 

[Chesmok]

I wouldn't trust a patch like that on even a small tank let alone a bigger one. Replacing the bottom could be really expensive too. I'd just sell this tank as a reptile tank and buy another used one off craigslist


Sent from my iPhone using Aquarium Advice

 

[squeegee_gal77]

Sent from my iPhone using Aquarium Advice

 

[squeegee_gal77]

The tank was filled prior to noticing the crack. There was moisture on the other side of the glass, but not dripping. So it held for quite awhile already.... There is no where for the crack to spread to, shouldn't that hold, if it's a water tight seal between the plexi glass and the bottom?


Sent from my iPhone using Aquarium Advice

 

[jrc0528]

Being as the crack ends at the holes, it cannot spread any more. As to structural strength, I would put the tnk in a safe area like a garage with a drain and fill it with as much gravel/sand as possible, then fill with water. Let it sit for a week or so and make sure it's up the the extra weight. As to the leaking at that crack, smear a good coat of silicone over the crack, install the bulkheads, and cover the remaining gap with a scrap of glass to protect the silicone. Of course, to be clear, the silicone is inside the tank, not under.