300 Gal beauty cracked bottom. Any hope to repair?

[J.Mcpeak]

No, I don't have glass work experience. Nor do I need glass experience to see the potential problems that arise from trying to patch a crack rather than replace the pane of glass.

You said it yourself that the cracked glass you patched was toast with a mosaic of cracks running through it.

My point is, that even if the chance of the bottom panel breaking is minute, the $200 ish dollars that it will cost you to buy a new panel of glass and replace it is miniscule compared to what could happen IF that failure were to happen.

Even assuming all repairs would be diy the damage to your house could EASILY cost thousands of dollars in damage.

There was a person on this forum that bought a cheap stand that got wet and failed dumping a 55g tank on the floor. If i remember correctly the repair bill was over $10,000.

The risk of patching outweighs the benefit.

I think you do need experience of glass and it's working methods to be boldly stating such things.

I have already agreed it would be best to replace the pane and not have a patch so that is a mute point.
On my tank.
Yes, the panel cracked but the glass spec was sufficent that it held up and no water was lost, one of four panes failed. No problem. (Laminated is 2 sheets normally, similar to front window glass in a car)

For the post,
The bottom panel that exists will most likely crack, as I noted by experience.
The replacement panel, this will cover completely the failed piece making the tank water tight.
There will be no problem except the glass falling from the bottom when the tank is moved, remember I said tape the base panel, standard practice that will prevent the panel separating while it is being moved.

It will be safe, uniform cross hatch at about 6-8" interval with gaffer type tape.

Then fit panel as advised. It will be safe, if you are confident with silicone it should not leak, providing tank is properly installed, level etc.

It really is straightforward.

I also said it would be best to remove the panel but it is not necessary.

A full sheet or two halves, silicone inside without removing the original piece.
Water tight.
Tape base panel for safety, to prevent injury to persons during transit.
Safe, secure.

What is the issue exactly?
You are more likely to have an o ring fail in the future spilling all that water than the silicone failing, or the glass repair, bearing in mind it is a full replacement.
Just cut time. It's exactly the way I'd do things.

You run more risk cracking side panels during deconstruction and properly remounting the glass to make a full repair.

If the base panel really concerns you and you don't like the gaffer tape look, use sticky back window film, secure anti entry type.

That will most certainly provide a safe and viable method for repair.
It will also be cheaper faster and just as safe long term despite the obvious failure in the sheet.

 

[54seaweed]

a buddy of mine fixed a 20g long this way
1 sheet glass on inside and sealed
1 sheet glass on outside and sealed
yes it held up about a week till it burst
20g water destroyed his new wood floor in his apartment cost him almost $3500.00 to fix , now imagine 300g the damage would be astronomical
if it costs more than 1/2 of what you paid for the tank ,
to repair it correctly consider it totaled
it may cost more for a new tank but at least you'll have piece of mind of not flooding your home

 

[mrgazza]

I agree with 54seaweed, the thought of "what if it did burst" would be enough to play on my mind making me worry all night long. 300gallons... Just imagine what that looks like on the floor. 1135 litres... 1.135 cubic meters... Sod that. Write it off or sell it as needing a repair then it's someone else's problem!


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[dylan p]

I would replace the glass. It's worth it. The only other option I can think of is plywood coated with fiberglass and epoxy.


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[Alan79]

Ok so heres another option. You could break down the tank and remake something differently shaped from the remaining panels.

Measure the longest sides and see if you have a third panel with no breakages that could fit as the bottom. Then cut end panels out of the last two un-broken panes. You will end up with a more regular shaped & smaller tank this way but you aren't writing the whole tank off.

For what it's worth i would attempt a repair myself. If the tank sits on a bit of wood that is cut to support the cracked base, it won't drop out. Lowering in another base over the cracked one should be about as good as redoing the entire base but in truth would probably come with some risks. Even the pond liner alternative has some merit if the wood that the tank is on is never removed. There would be some risk of leakage around the corners though. Any tank is a risk of breaking whether it's brand new or something that you have patched up already.

I'm interested in seeing what you end up doing. I hope it works out well for you.

 

[militantpotato]

Wow. If that pops flood insurance won't cover you. The only things I'd do with that is find a tank builder to fix it, replace the bottom with a plywood and fiberglass job (similar to a diy tank,) or scrap it.

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[dylan p]

That's what I said. I think glass would be the best tho those diy aquariums use mostly water pressure to hold the glass in place. The silicone doesn't stick to great to the epoxy it could work since it's on the bottom. If you do that put paper all the way around the bottom and only fill it part way for a couple weeks if there's any moister coming through you will see it on the paper and you can drain it b4 it becomes a problem


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[J.Mcpeak]

3500 to fix 20gals water? That's 80 litres or so, seems a little steep! Was it in a block of flats or something? Maybe that could cost so much, 50litres is easy to mop up from a vinyl floor.

It isn't 300g but my big tank (750litre DIY) is 198 us gals +filters at the moment, it'll hold more (1020 on paper) but displacement of substrate. Same twin skin, the inside panel is enough to make watertight. If I spent all day worrying about it bursting what is the point of keeping fish! Too much stress! Test fill it, if it doesn't leak it will not suddenly burst unless you have not set up properly in the first place. I admit I worried for a few days but years later, it still works. The second skin was my built in failsafe.

Essentially you are replacing the broken pane while leaving existing glass in place using glass and silicone the same way the tank was originally built, how can it suddenly catastrophically burst? If this happened they wouldn't be selling them as they would be considered unsafe!

Hi Al, how are things? Told you I'd be back!
Yes who did that? Make a new tank with an old one? Was that you?

The worst thing that happened so far, a failed valve on the filter lost some 200 litres (52g)
It dried out no problem but it was a stone floor, on carpet maybe you would need to clean carpet, a tank like that on a first floor (I think that's 2nd floor in USA) on timber is always going to go wrong! If the wood beneath isn't up to it it will fail. 300 gals is over a ton, plus tank plus rocks plus you! That's more like 1.5+ ton that's 3300lb. BIG WEIGHT! I wouldn't put that on a timber floor! You need concrete and a perfectly level and evenly supported tank.

 

[PB_Smith]

Has the OP revisited this thread recently?
The smartest move would be to try to seek some remedy from the tank manufacturer, it was a brand new purchase after all (I did say just tell them it happened at first fill).

If it does come down to a DIY repair, it can be done,
BUT!!!!!!!
the most important thing to do to insure against failure is to find some way to fully and completely support the entire bottom pane of glass. That way there is no force exerted on the glass itself, but rather is transmitted to the wooden stand structure.
It is having that 1/8"-1/4" gap under the bottom plate that is the issue.


Fully support the entire bottom, and the full piece patch would work.

 

[PB_Smith]

a buddy of mine fixed a 20g long this way
1 sheet glass on inside and sealed
1 sheet glass on outside and sealed
yes it held up about a week till it burst
20g water destroyed his new wood floor in his apartment cost him almost $3500.00 to fix , now imagine 300g the damage would be astronomical
if it costs more than 1/2 of what you paid for the tank ,
to repair it correctly consider it totaled
it may cost more for a new tank but at least you'll have piece of mind of not flooding your home

I'll bet he just slapped them on and left the gap under the tank. If patched that way, what do you expect?

the idea is once the bottom piece has cracked, it's integrity is compromised and the only way to get around it is by fully supporting it so no pressure is exerted on the glass bottom, but transferred to the stand.
simple physics...
then the only way the bottom could fail is by concussive force, concentrated crushing forces or twisting/shearing forces, none of which you would encounter in a common aquarium set-up, unless of course you drop a real heavy rock onto the bottom glass.

 

[dylan p]

If you decide to get rid of it message me I'll buy it


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[J.Mcpeak]

Smooth!

 

[Alan79]

3500 to fix 20gals water? That's 80 litres or so, seems a little steep! Was it in a block of flats or something? Maybe that could cost so much, 50litres is easy to mop up from a vinyl floor.

It isn't 300g but my big tank (750litre DIY) is 198 us gals +filters at the moment, it'll hold more (1020 on paper) but displacement of substrate. Same twin skin, the inside panel is enough to make watertight. If I spent all day worrying about it bursting what is the point of keeping fish! Too much stress! Test fill it, if it doesn't leak it will not suddenly burst unless you have not set up properly in the first place. I admit I worried for a few days but years later, it still works. The second skin was my built in failsafe.

Essentially you are replacing the broken pane while leaving existing glass in place using glass and silicone the same way the tank was originally built, how can it suddenly catastrophically burst? If this happened they wouldn't be selling them as they would be considered unsafe!

Hi Al, how are things? Told you I'd be back!
Yes who did that? Make a new tank with an old one? Was that you?

The worst thing that happened so far, a failed valve on the filter lost some 200 litres (52g)
It dried out no problem but it was a stone floor, on carpet maybe you would need to clean carpet, a tank like that on a first floor (I think that's 2nd floor in USA) on timber is always going to go wrong! If the wood beneath isn't up to it it will fail. 300 gals is over a ton, plus tank plus rocks plus you! That's more like 1.5+ ton that's 3300lb. BIG WEIGHT! I wouldn't put that on a timber floor! You need concrete and a perfectly level and evenly supported tank.

About time you were back. I wasn't here much while the NRL season was running. Do we need to poke and prod you to get your reef running. I don't feel ready for reef yet so i'll live vicariously through yours

I've done a bit of tank recycling now. I used a 3 foot standing tank (4x 3 foot panels of good glass) to fix a 40g (cracked end panel) 30g (cracked end panel). Now with the leftovers from the 3 foot standing tank (3x 3 foot panels) i am 2 end panels away from having another 3 foot tank to fix. In the end i will have 2x 30g + a 40G that i'll have thrown together for about $80

 

[J.Mcpeak]

About time you were back. I wasn't here much while the NRL season was running. Do we need to poke and prod you to get your reef running. I don't feel ready for reef yet so i'll live vicariously through yours

I've done a bit of tank recycling now. I used a 3 foot standing tank (4x 3 foot panels of good glass) to fix a 40g (cracked end panel) 30g (cracked end panel). Now with the leftovers from the 3 foot standing tank (3x 3 foot panels) i am 2 end panels away from having another 3 foot tank to fix. In the end i will have 2x 30g + a 40G that i'll have thrown together for about $80

That's it I remember now, end panel, did you make a thread because I remember seeing pictures of a disassembled tank. Was that you? I think it may have been? If it wasn't your own thread it was "what did you do with your tank today."

Have you filled them yet or is the niece still giving you "a talking to"

(Not a rugby fan, sometimes I watch it but it all stops the the BTCC!
Yes I need some extra encouragement on the reef, I almost had it but I got a new camera instead. I got reef books, a big bucket of salt and a refractometer so far. Im happy about the new toy but I could've got pumps/plumbing, rocks/sand, wave maker and ATO instead. I think I'll wait until January before I buy anything now.)

Please feel free to usher me!
(Forgot to mention Brutus! Sorry, how is Brutus?)

 

[myDorazio]

Update from OP.

Sorry I did not check back on your answers. I've been too busy prepping for XMas vacation at work, which started today!

Thanks to you, I'm almost ready to do the fix, but I am unsure if I will try to add another 1/2" of glass shaped to cover the cracked full bottom plate or simply use a pond liner held in place with Marine Adhesive 5200 to stop the leak. Attached are pictures from underneath of why I think I might get away with just the liner:

I hope you can tell from the pictures that the 1/2 inch glass bottom plate(the one with the crack) is sitting directly across its entire surface on 5/8" plywood, that is attached to the tank and trim. That structure (tank with wood and trim) sits on top of another 5/8" plywood that is the top of the stand.

So given that situation, quotes like these give me a lot of hope:

Alan79 wrote:

If the tank sits on a bit of wood that is cut to support the cracked base, it won't drop out... Even the pond liner alternative has some merit if the wood that the tank is on is never removed.

Yes, definitely never. We're in our 50s and hopefully won't be moving any time soon.

PB_Smith wrote:

...the most important thing to do to insure against failure is to find some way to fully and completely support the entire bottom pane of glass.

Yes, the entire area of the bottom plate (except for the small areas drilled for piping) are supported directly by two layers of plywood.

J.Mcpeak wrote:

I will say, the best way is to replace the bottom panel but it is not necessary.

The "not necessary" is very hopeful. However, there is no denying that everyone agrees that this is not the best way:

Mebbid wrote:

The only way to safely do it is to replace the bottom piece of glass.

Fishfur wrote:

But stress over time might one day still result in a major disaster.

I believe I should be OK because the two fairly thick (5/8") layers of plywood are directly beneath the weight of the bottom plate, with no gap. It would be great if I had the expertise to replace the bottom plate, but this is a very oddly shaped custom wrap-around made by Dutch Aquarium Systems with a lot of odd angles. I could barely replace the rectangular wood that rotted out underneath my garbage disposal, so I don't dare try to measure and have cut for me some expensive 1/2" glass to try to fit it.

My question is that even understanding that we risk $10k+ of damages if this shatters catastrophically, would those of you who have experience with these types of builds feel comfortable with this in your living room with just a liner fixing the leak and no additional plates of glass on top of the side-to-side crack in the bottom plate?

 

[myDorazio]

My hope is that someone with experience with large tanks will tell me "with 1/2 glass sitting directly on top of two layers of 5/8" plywood, you should be fine" but this morning an aquarium installer in town told me that the risk is too great. We could put in a pond liner but if the leak ever reoccurs (because of, for example, minor seismic activity), the wood underneath could start getting wet and if we don't notice that the wood gets wet (which seems like a possibility) then a few weeks later the whole bottom can fall out--both layers of wood and the bottom plate. Then we've got 300 gallons of water sloshing around in our living room and $10K+ of damage that insurance won't pay for.

He also recommended rebuilding with new glass, but unfortunately nobody does that work except hobbyists.

 

[Fishfur]

To be honest, I think you're far too optimistic about this. You've already spent a large sum of money on a custom tank. Why cheap out now and do a half assed repair, before trying to get it done properly, which may well be possible.

There are companies in the US that do build custom tanks and might be able to do a repair like this. Two of them have or have had TV shows about their work, finding a company that does this kind of work can't be very difficult, though it may cost to get them to where you are. The TV guys mostly show work in acrylic, but they must be able to also work in glass, or know people who do.

For me, by far the greatest worry is absolutely the insurance liability you may face if the repair fails. It could potentially be an enormous amount of money that might have to come from your pocket, most particularly if any personal injury results from a failure.

I don't know what you paid for this tank, but is it truly worth this level of risk to attempt cheap repairs ? Have you actually made an effort to get it done right ?

I'd try calling some of the aquarium manufacturing companies to see if they have anyone on staff capable of doing such a repair. They might not offer the service themselves but perhaps they'd let you get in touch with such staff members and make your own deal.

I'd call some of the larger glass companies. The ones who handle large custom contracts must be capable of cutting a new piece of glass to the exact measure needed, they must have some expert glass cutters. If you can get the glass cut, sure, chances are they would not be willing to install it, but maybe then you could get some help to install it. Replacing a panel isn't rocket science exactly but it does have to be done correctly and the sheer size of the thing makes it a challenge.

It all comes down to money really. How much can you afford, either now, for repairs, or later, for disaster.

I know you hate to waste what has already been spent, and seeing this tank sit there unusable must be so frustrating. But first I'd want to exhaust all possibilities of having it done correctly, so you won't have to worry about the what ifs later.

So can you afford the potential damages down the road ? This kind of tank is such a big investment, and if it were it mine and I had to save up for a year, I'd be saving up to invest in having the repair done right.

Optimism is a wonderful thing but unfortunately, reality can really bite.

 

[Nathenrauch]

To be honest, I think you're far too optimistic about this. You've already spent a large sum of money on a custom tank. Why cheap out now and do a half assed repair, before trying to get it done properly, which may well be possible.

There are companies in the US that do build custom tanks and might be able to do a repair like this. Two of them have or have had TV shows about their work, finding a company that does this kind of work can't be very difficult, though it may cost to get them to where you are. The TV guys mostly show work in acrylic, but they must be able to also work in glass, or know people who do.

For me, by far the greatest worry is absolutely the insurance liability you may face if the repair fails. It could potentially be an enormous amount of money that might have to come from your pocket, most particularly if any personal injury results from a failure.

I don't know what you paid for this tank, but is it truly worth this level of risk to attempt cheap repairs ? Have you actually made an effort to get it done right ?

I'd try calling some of the aquarium manufacturing companies to see if they have anyone on staff capable of doing such a repair. They might not offer the service themselves but perhaps they'd let you get in touch with such staff members and make your own deal.

I'd call some of the larger glass companies. The ones who handle large custom contracts must be capable of cutting a new piece of glass to the exact measure needed, they must have some expert glass cutters. If you can get the glass cut, sure, chances are they would not be willing to install it, but maybe then you could get some help to install it. Replacing a panel isn't rocket science exactly but it does have to be done correctly and the sheer size of the thing makes it a challenge.

It all comes down to money really. How much can you afford, either now, for repairs, or later, for disaster.

I know you hate to waste what has already been spent, and seeing this tank sit there unusable must be so frustrating. But first I'd want to exhaust all possibilities of having it done correctly, so you won't have to worry about the what ifs later.

So can you afford the potential damages down the road ? This kind of tank is such a big investment, and if it were it mine and I had to save up for a year, I'd be saving up to invest in having the repair done right.

Optimism is a wonderful thing but unfortunately, reality can really bite.

Well said.


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[myDorazio]

Thanks for the advice. I will contact the manufacturers and some more local glass people (a few have turned us down) and see if we can't do the repair correctly. I appreciate the help.

 

[BillD]

I skipped through most of this thread, but will add some. The local Big Al's had the bottom crack on their 780 gallon shark tank. It was an inch thick glass, 4" x 8'. They repaired it with a patch on the inside. I was there when they assembled the tank, and must say, I was surprised to see it had broken. The bottom seemed well supported.
I did see a pictorial of a 16 foot tank being built and the bottom was made up of two 8" pieces with a patch over the joint. The entire bottom was supported so there should be no shifting of the joint.
In this case, I would not put the bottom directly on plywood, but rather, would place the tank on styro that sits on top of that plywood. There is always the risk, with wood, of warpage which would be negated by the styro, while at the same time fully supporting the entire base of the tank so their is no bottom flexing.