DIY Tank Repair? (broken bottom glass)

[ItchyF1ng3rs]

Hey AA! Love the site! Give it a vote everyday!

I have a 125g tank that the bottom broke on me about 4 years ago. (Engineer goby shifted sand and LR came crashing down) Good news I found that I have beautiful wood floors under the carpet. My wife and I refinished them and they look great!

Any-hoo, I have moderate-to-good DIY skills and was wondering if you think that putting a new panel in the bottom is do-able? The ultimate goal would be to use this aquarium FOWLR or possibly turn it into a sump for a larger reef one. But that is far in the future. I'm just looking at fixing this one right now.

I found a local glass retailer that can get me a 72" x 18" x 3/8" panel for around $80. I realize that the bottom isn't tempered by the way it broke but is there anything special about aquarium glass that I should know about? I thought about going to 1/2" for added strength.

Thanks for your advice!!

 

[mfdrookie516]

my 125 has half inch glass... and its tempered. Acrylic is way stronger, but im sure its way more expensive too... something like that could prevent the bottom from breaking again due to rocks crashing down? just a thought. i would certainly go with 1/2" though

 

[thominil]

+1 on the acrylic. Much tougher than glass and will help prevent the breakage on the bottom again.

 

[mfdrookie516]

i just re-read my post, i meant i would at least go with 1/2" glass... if you can afford it, go with acrylic

 

[thominil]

Welcome to AA as well!

 

[partypalooza5]

I may have misunderstood, But if he has a glass tank, how are you going to get an acrylic bottom? I thought silicone didn't stick to acrylic..

 

[thominil]

hmmm....weldon?

 

[mfdrookie516]

silicone will stick to acrylic if you do it right, i siliconed a windshield for a race car and as long as you take rough sandpaper to it where you want the silicone, it will stick...

 

[partypalooza5]

Ah ok. I learned something today!

 

[BigJim]

If you put an acrylic bottom in this glass tank, would you set it up like a glass tank or an acrylic tank? I assume it would have the plastic frame around the bottom still, but I'm not sure the acrylic is rigid enough to resist flexing if it's not fully supported.

 

[jsoong]

I would be nervous replacing the glass bottom with acrylic .... many had posted of acrylics baffles falling apart when silicone .... I wouldn't chance a non-standard construction technique with a big tank full of water!

Personally, I would go with glass. Most newer tanks have tempered bottoms to reduce weight & thickness. My old 75 has untempered bottom & it was 1/2", with a new one it is 3/8" tempered. The new 125's are 1/2" tempered, so you might just want to go a bit thicker than 1/2" with untempered glass. I would protect the bottom of the glass tank with a sheet of plastic eggcrate. <On top of glass & under the rocks/substrate.> That would help prevent stress fractures like your original incident.

Otherwise, replacing a glass pane is not too difficult, with moderate DIY skills.

 

[ItchyF1ng3rs]

Thanks for all the replies. I am going to order 1/2 glass I think. I'll document my progress... but don't get in a rush it will be slow, first I have to get the old glass out

 

[super-duty]

Just curious why would you take it apart? I fixed a 100g that had a crack in the bottom with 3/8 acrylic. I left the cracked bottom in and cut the panel 1/4 shy that left me an 1/8 inch gap all the way around. I layed in some silicone in just flush then came in a few days later and put a radius of silicone in and used it for 3 years bofore I sold it and it never leaked.

Maybe that was like like shooting craps but it worked for me.

 

[jsoong]

Just curious why would you take it apart? I fixed a 100g that had a crack in the bottom with 3/8 acrylic. I left the cracked bottom in and cut the panel 1/4 shy that left me an 1/8 inch gap all the way around. I layed in some silicone in just flush then came in a few days later and put a radius of silicone in and used it for 3 years bofore I sold it and it never leaked.

That is a standard way to repair a cracked bottom, although you are supposed to use glass on glass (with silicone) & acrylic on acrylics (with weldon).

Some of the old tanks are made with 2 bottom panes, and the seam was sandwiched with glass (both on top & below). This seems to work fairly well. Siliconing a piece of glass on top of a crack is the same thing, except that you didn't planned the crack/seam. One disadvantage of this for a big tank is that it will really increase the weight of the tank.

 

[ItchyF1ng3rs]

Just curious why would you take it apart? I fixed a 100g that had a crack in the bottom with 3/8 acrylic. I left the cracked bottom in and cut the panel 1/4 shy that left me an 1/8 inch gap all the way around. I layed in some silicone in just flush then came in a few days later and put a radius of silicone in and used it for 3 years bofore I sold it and it never leaked.

Maybe that was like like shooting craps but it worked for me.

Hey Super-Duty,
I haven't had a chance to take pictures of the broken bottom, but it would be clear why I need to remove the glass. Most of it is gone anyways and there wouldn't be enough to attach to. That would be a neat idea if it worked for my case. Thanks for the idea.

 

[super-duty]

I would take a pic so we can see what you are workin on. When I did mine the bottom was all there it was just cracked from front to back. That is why I think I got away with it. If you have sections missing I think you may want to flip it upside down and pop the trim off and have a new bottom cut. If parts of it are still in tact it isnt tempered so you do not need to replace it with tempered. I am sure you could lay a new bottom in there and get away with it but you would have to use glass because there is sections missing and no way to support the acrylic.

 

[SparKy697]

Thanks for all the replies. I am going to order 1/2 glass I think. I'll document my progress... but don't get in a rush it will be slow, first I have to get the old glass out

I picked up a 125 with a broken bottom a few years ago. It also had pieces missing. At the time they wanted a close to 200.00 for a piece of tempered glass to match what was there. I went to work taking the bottom glass out, that's when I decided that it was not worth it.

It seems to me that the logical thing is to use tempered glass like pretty much the whole industry does, but for the cost and labor involved it just did not seem worth it to me. Plus the ever present chance that you will do something not quite right and have even the smallest leak....

What does a new tank cost?

 

[ItchyF1ng3rs]

Here are some pics:

Whole tank:

Right Side:

Left Side:

In the bottom of the leftside pic you can see the glass is missing all the way under the trim.

I'm going to start working on removing the trim from the bottom.

 

[FishEggs]

ouch

 

[super-duty]

Yea I think that is all you can do. When you go to the glass shop I would ask them how much it is to temper it just to see what the difference in price is. Not all bottoms are tempered so it is a judgment call.