Cracked Tank

[Sjoerd]

Hi,

My son has a marine tank and prompted my interest in marine fish. I am new to marine fish and decided to have a 960 litre (220G) glass (12mm/ 1/2 inch) tank - fish only - built by a local company. Everything done and installed - 100kg (220 Pound) aragonite sand, natural rock 200kg (440 Pound), added water and salt and started the cycle period. Everything OK for two days but the tank cracked on the bottom glass panel. Fortunately we were at home and drained the tank. Now we wait for the contractor to advise what to do.

We still have to dismantle the tank and see exactly where the tank cracked, determine why the tank cracked and find a remedy.

I am not sure what the contractor will advise and hence my question is - what would be the best option to repair the tank?
The internet offers different opinions but I would like to hear from the forum

Looking forward to hear

 

[Mishri]

it looks like your stand is smaller than your tank? that isn't good. it's possible you could silicone the crack.. but I wouldn't trust it. I'd want a whole new bottom pane.

 

[Clowning_Around]

Check entire perimeter of tanks base against the stand for gaps, there should be none not even small. If so this is a prime culprit, it creates uneven bearing amd pressure points typically cracking the glass. Also the stand footprint should at a minimum be equal to the tanks footprint. If it had been a side panel that cracked I would likely attribute it to this, and on that note could still occur after you fix the other matter at hand. Gluck, sorry for the crack.

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[Vinny Kreyling]

New Tank + New Stand

 

[Clowning_Around]

Wow i was able to look back at the pic on a screen larger than my phone, that stand is way to small, im surprised you didnt have a more catastrophic failure (blowout). Those cantilevers paired with the already outward pressures on the side panels is most likely creating a downwars force at edges and a upward/bowing force in the center countered by the weight above mostly but I suspect thats the real culprit

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[Clowning_Around]

See if the tank builder will replace the bottom and then get a new stand, or rebuilt the current correctly. Thats the bandaid approach, otherwise replace it all. You could make a sump from the old glass if you do go that route

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[crimsonblue]

The outside walls and seams of aquariums get a lot of stress from the weight. Hanging over the side, it never had a chance. Unless the tank manufacturer (or person who sold it to you) recommended this approach, you're probably buying a new tank and stand.

Sell it off a turtle/iguana terrarium to recover a small part of the money.

 

[Sjoerd]

Hi,

Thanks for the advice - we should have the tank cleared of everything and assess the damage. I will keep you posted

 

[Sjoerd]

Hi,

The tank was placed on a sheet of pressed wood. From the pictures one can see the overhang on the steel structure and on the pressed wooden sheet. The tank cracked along the middle of the glass and also diagonally across where the "overflow & return flow" pipe comes through the bottom - see pics

What importance would a thermocol sheet play when placed on top of the pressed wood sheet?

I'll keep you posted when I hear the final recommendation from the contractor how to fix the problem

Wait to hear from you

Thx

 

[gavinbree]

You'll still have an over hang
Even with the wood in place, you are basically putting all the pressure in the centre of the panel with that and is why its cracked the bottom.
With a tank that big you have to be sure the base/stand is as level as possible and covers the whole length of the tank.
I would get a metal frame made and get it welded to the top of the stand if you are adamant you want to keep the stand.

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[Mishri]

I agree, that still isn't going to work for a stand for the aquarium. Your stand must, at minimum, reach the edge of the tank, larger than the tank is fine.

You need more center support as well based on the picture of the stand. in the DIY section there is a thread on how to build a stand.

your aquarium weighs 166kg empty, 973kg of water, plus your rock/sand weight. you need to build a stand capable of not only supporting that, but not bowing under that weight, including left/right, forward/backward movement. Previous owner made that mistake with the stand he made for the 300 gallon I have. He made it support the verticle weight, but once he had movement, especially from large fish, the whole tank and stand would rock back and forth. Large Aquariums need a lot of support.

 

[d-man]

In that last pic, is that silicone all over? If so that is the worst job I've ever seen. You need a full refund for sure if the company told you the stand was ok and the tank was ok for that. That by all means is a terrible catastrophe

 

[BZOFIQ]

Recipe for disaster!

 

[Alfrareef]

Please get a new tank and a new stand with center support.

 

[Clowning_Around]

In that last pic, is that silicone all over? If so that is the worst job I've ever seen. You need a full refund for sure if the company told you the stand was ok and the tank was ok for that. That by all means is a terrible catastrophe

Wow. Speaking of silicone, despite the focus on the cracking, it looks as if that is the only thing around the pipe penetrating your bottom panel, which is another leak waiting to happen.

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[Sjoerd]

Hi,

The contractor's opinion why the tank cracked is that the rocks inside the tank was to heavy (we did not weigh the rocks but my estimate is that the rocks are between 200 and 300kg (440 to 560 pounds)

The contractor's solution to fix the tank is:

"we should affix a much thicker glass (15 or 19mm) on the bottom from the outside (onto the cracked bottom pane) and put braces on the existing glass (bottom cracked pane) from the inside"

The contractor recons that the overhang is not a problem because he has built 360 gallon tanks on the same principle without any faults

Wait to hear

 

[ca1ore]

I would be most suspicious of said 'contractor'. It doesn't seem like they know what they are talking about. Rock isn't all that much heavier than the water, frankly. I've kept large tanks with much more rock than that without problem. OK, it is possible point loading popped the panel, but I think an insufficient/poorly designed stand or too thin a bottom is far more likely to be the culprit. Patching a new panel over the cracked one seems like a spectacularly bad idea. Shocked that any credible tank manufacturer would even suggest it. How thick was the original bottom, if 15mm is 'much thicker'. If it's 12mm on the bottom, that seems way too thin (even for a non suspended bottom). My 265 has 12mm on the sides but 19mm on the bottom. Silicone looks like a major hack job, and for a tank that sits flat on the full bottom panel, some kind of cushioning is almost always required.

 

[Alfrareef]

With those contractor options you're heading to disaster. He should rebuild the stand covering tank base and with more central support. Also he must replace the bottom panel and inspect side silicon looking for stress faults. Don't let him persuade the other way around.

 

[DivingTheWorld]

Based on the pictures of that highly questionable stand pipe, silicone work and inadequate stand, I suggest you move for a full refund and go with a different manufacturer. Sticking with that manufacturer is going to end in disaster. IMO they have no business building tanks.

 

[Clowning_Around]

Revising prior suggestion... New suggestion, get new tank, get new stand and get new contractor!

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