Used 300 gallon tank has a broken bottom

[RecycledElectrons]

I picked up my (free because it leaks) 300 gallon glass aquarium. It measures 96x24x31 and has dual overflows. I got it home, and realized that the bottom has a 2 foot long crack in the back 4 inches, starting at one of the overflow holes and ending at the back edge.

I am not able to buy a new piece of glass to redo the bottom, and there is no way to seal this thing with patches.

The silicone is in bad shape; I can see water intrusion under the silicone in many places.

I am thinking about cutting it apart, but there are glass pieces (2" x cut-to-fit x 1/2") in all the seams. I am not sure how hard it will be to remove them.

Then there's the bottom. I had given up home for a while until I remembered that a guy in Career Technology Education (CTE) with has a glass cutting water jet at work. (I am building this take for my school. I am a teacher.) Maybe he can cut the parts down so this 96x24x31 becomes a 96x20x31 or a 96x18x31.

I am interested in any experiences people had with similar situations.

 

[burntrubber]

In my opinion, it's too much work to rebuild the tank. All the silicon has to be new. Patch up what you can and turn it into a terrarium. You can put critters like reptiles, amphibians and crabs.

 

[Zex Marquis]

I have a 265 that I'm debating on taking apart and using the glass for a plywood build. Not sure yet because the tank is still in good shape. But in your case I would definitely go that route

 

[RecycledElectrons]

> Patch up what you can and turn it into a terrarium. You can put critters like reptiles, amphibians and crabs.

That is a very interesting idea.

 

[fishdance]

Why aren't you able to seal the bottom with internal patches? I've sealed several bottom cracks with glass, slate tile and once even with sheet metal strip. The patches don't need to be neat if covered by substrate. Silicon is very forgiving and can span 10mm gaps. You are just stopping water from getting through the crack.

Another less convenient option would be to patch from the outside by putting on a second bottom. Again this does not need to be a single sheet of glass.

 

[TheReefer]

I agree with fishdance, I have done that before too. Just get a glass/plastic panel that fits over it and silicone it over top of the crack and then cover it up with substrate.

 

[Backfromthedead]

I also agree with fishdance and reefer. Ive made plenty of sturdy repairs with some silicone and glass panels.

Forget the terrarium. Fish are where its at and reptiles smell terrible.

 

[duanes]

I have also sealed cracked bottoms, by removing old silicone and putting a pane of glass over the crack, using more silicone on the crack, where old silicone was, and around new glass pane edges.
The only time it doesn't work, is if the water pressure from within pushes the sides panels apart because of a compromised frame, then eurobracing would be needed.

 

[RecycledElectrons]

The problem with patching is that:

(1) There are existing panes of glass siliconed to the bottom where it meets the edges. (I do not know if they were to seal a previous leak or to reinforce the bonds to keep a side from falling off.) The crack extends all the way under those reinforcing piece, to the back edge of the bottom piece. There are lots of places where the water can leak under those reinforcing pieces. Then it can flow through the crack. Even if I put a new piece inside, and a new piece on the bottom, I will still need a piece on the back to stop water from leaking through. My experience has been that complicated (multi-piece patches) do not work.

(2) in a 2.5 foot deep aquarium, the water pressure should be 72 pounds per square foot at the bottom.

The problem with rebuilding it is:

(1) I do not think I can get those reinforcing pieces out. They are all over the aquarium.

If I do get them out, my coworker has a CNC water jet for cutting class that can cut up to 5ft x 10ft to 0.005 inches accuracy. So I can cut things if I get it apart.

(2) If i have it all apart, I do not think I can resilicone all those pieces together before the silicone gets a film.

The terrarium idea is looking better and better.

Edit: When you look at the pics, please know that the aquarium is up on furniture dollies at the moment.

 

[Backfromthedead]

Well if terrariums are your thing then that is a good option. I completely understand not wanting to get into all that. Those existing glass strips really make it a much more difficult job. But still doable if you have the time and determination imo.