Is this crack serious?

[Mr31415]

I discovered a crack on the bottom of my 480g tank...

It runs from front to back for about 10cm between the centers of the two bulkheads, and about 1cm past one of the bulkheads.

As far as I can see it is only the bottom 10mm glass pane that is cracked - it seems the other 2 x 10mm panels are still intact (but this is difficult to verify). The base is made up of one solid 10mm panel, and two layered 10mm panels on top of if for a total thickness of 30mm (1.2").

Is this a major cause for concern? Or should I just watch it? No water is leaking from it - it is located in the overflow section. Here is a simplified drawing of the underside of the tank:

 

[nsreefer]

I would say yes, very serious. If something caused one pane to crack the other two will likely crack as well. I would call your tank builder and see what they have to say. I am assumig that this tank is custom?

 

[easye123]

ya i would take every bit of it seriously with a 480g tank.. I would be somewhat prepared to tansfer if that crack gets bigger

 

[Mr31415]

Yes this is a custom tank. I called them and they assured me it is nothing to worry about - that there is still 2 x 10mm glass panes that seals the water and that is not cracked.

This means they will not fix it for me...??

 

[Ehgemus]

Ask them if they will rebuild your house if it breaks?

 

[joekr]

Me personally, I would not risk it. That is a LOT of water to gamble with. Given that the two holes drilled are where the crack is occurring, I would guess they may have been too close or the glass in that area was weak to begin with.

I would be running out to get some of the 100 gallon rubbermaid feed containers and moving everything out of the tank.

Why did they not choose to go with one solid piece of glass rather than layer 3 pieces together? Are the 3 pieces bonded together by glue or are they just laying on top of each other? I have never heard of a build like what you are describing, but this is possibly ignorance on my part...

Good luck!

 

[sjm817]

Hard to say. The bottom is made of (3) 10mm panels sandwiched together, but just the bottom panel has the crack? Are the 3 panels bonded together? This is glass or acrylic?

 

[flfirefighter13]

if the manufacturer is saying the crack is ok then find out why they put the glass there in the first place..... Its rather rare to see a comapny put extra labor and materials into a project just to spend extra money, and if they are telling youa crack is no reason for concern that must have been what they where doing. Demand a new tank.

 

[Mr31415]

joekr - it is quite standard in SA. Supposedly the shipping is too expensive for a 19mm sheet - so instead they silicone two 10mm pieces together - or three in my case.

sjm817 - yes they used silicone to join them. The bottom panel is one single sheet, the upper two layers are panels - about 400mm wide fitted snugly next to each other, all siliconed together. It is glass. In SA a glass tank like mine costs R12000 (roughly USD 1200) and an equivalent acrylic costs R45000 (roughly USD 4500). So I just cannot afford it. Nobody here uses acrylic for residential aquariums.

flfirefighter13 - the first tank they built broke a month ago - 2 days after I filled it to the top. That tank had a little weaker base (38mm square tubing frame - new one has 50mm aquare tubing frame), and the old one had 2 x 10mm bases - the new one has 3 x 10mm bases. I demanded a replacement when the first one broke and so they did without charging me - the problem is just if I have to redo all this work again for the third time I'd rather not have the tank at all - since how would I be guaranteed it will not break a third time? And with a crack like that it is easy for them to say I broke the tank when I fitted the bulkheads - that I overtightened them (this after they told me I cannot crack a 2 x 10mm base with a bulkhead by hand even if I tried).

So... Unless I am going to replace that tank on my own cost and have to wait another 2 months and spend all that money on RO/DI water and salt - I guess I have no option but just to monitor that crack. If it gets bigger I'll try to convince them to somehow fix it... Just everytime they take that tank in/out my house they scratch the front door since the tank barely fit through the door so I am really tired of all this nonsense.

 

[nsreefer]

I'm not trying to scare you, but when a tank that large fails, they don't just crack and leak, they have a tendancy to explode, sending a tsunami of shards of glass and seawater out at a very high rate of speed. This is due to the tremendous pressure that that ammount of water creates within the tank. Not only could this cause incredible damage to your home, but serious injury should anyone be in the room when it fails. I would advise not taking this crack lightly. Cracks don't stay the same size generally, they get bigger.

 

[Sk8r]

I tend to agree with the alarmists. However, you might measure the floor with a very short spirit level and see if you've had any swag develop that could account for it, and if the area is dry, you might run a line of silicone sealant to hold it while you start prepping for another tank. If the tank is emptied short of failure, it could still be viable as a terrarium, if you've any contacts to be able to market it for that use. Somebody who keeps, say, monitors or large iguanas might be interested.

 

[Mr31415]

nsreefer - I know - like I said, the first one broke. 1800l on the floor in the living room within 1 hour - a crack 2.7m long...

Sk8r - the tank is up and running for 3 days now... The stand is very close to level - it drops 5mm over the 2.7m length. Interesting you mention the terrarium idea - my wife and I went to the yearly reptile and marine aquarium show in our country and I jokingly mentioned to my wife that if that tank breaks I am going to stuff it with cute monitors and gecko's...

 

[jacmyoung]

I was reading your tank build thread just a few days ago, are you saying your tank bottom was made of three layers of 10mm think glass pieces glued by silicone throughout the entire contact areas of the layers?

Did you notice the crack just now? Do you know for sure that crack was not there before? Did they drill the holes after the panes were put together and glue all cured? Drilling through three layers of glass stacked together could be the problem.

I'd fine out everything about how the glass were put together and how the holes were made, and ask them to put in writing a warrantee against future leak. Of course your first tank was busted so confidence in that builder is seriously compromised.

 

[csb]

I wouldn't let history repeat itself... your previous tank from the same people already broke. This one has a crack and you're questing whether or not it's going to be alright.

If I were a betting man... odds are against the tank. Sorry man, but that's just reality. IMHO, the tank should be replaced with one by a different manufacturer.

 

[DouglasTiede]

is there any hope of putting another piece of glass over the exising one and thus sealing in the crack?

 

[BigBadBlenny]

i see your as cursed as i am. my wife and i call this going pear shaped. welcome to the club

 

[Mr31415]

jacmyoung - yes and no. Three layers of 10mm siliconed together but the silicone does not fill the whole area - it is mostly on the lines where the panels are joined. The silicone strips are about 6" wide...

The crack - it was definitely not there two days ago. Only noticed it yesterday. No they drilled them separately and I know this because the holes do not align properly.

DouglasTiede - I could do that but would it make a difference? If the crack runs it will run whether another piece of glass is underneath it or not? Or am I wrong?

As I see it (taken everything into consideration) I have two options.

1) Tear down the tank right now, get another manufacturer to replace the 3 x 10mm panes with maybe 1 x 1" or 1 x 19mm + 1 x 10mm layered on top of it at my own cost and start all over again.

2) Wait it out - monitoring the crack for at least one year (winter/summer cycle) and if it does not grow at all keep on praying it does not break...

Depends on whether I am a gambling man I guess. It's just that the first time setting up a tank like that is great fun - the third is NOT.

 

[crazyguy34834]

man, I can't think why you got another tank from the same people that your other tank came from. I would have demanded a refund and had someone else build it because they are doing something wrong.

By the way, GET AN ACRYLIC TANK, save up for it because almost 500g is A LOT OF WATER. I have an acrylic 100g tank and I am very happy with it. I never have to worry about it breaking as acrylic can hold over twice the pressure as glass can.

You could build the tank out of cement and have acrylic viewing panels.

All that water on the floor and you didn't have any water damage?
Think haw much money it is to repair damage and what is lost when your tank breaks and then think about the cost of an acrylic tank.

 

[Mr31415]

crazyguy - as I mentioned somewhere else the difference here between glass or acrylic for this tank is R12000 or R45000 (USD 1200 or USD 4500). That is just too much.

Yeah I had someone within 2 hours come remove the furniture from the living room and clean up the mess. I was lucky.

 

[crazyguy34834]

I don't know how you are viewing this tank but a tank that big must be built into the house. I would go with cement blocks reinforced with rebar and put an acrylic viewing panel in it. I would definately save up and do this if you are going for a big tank and have some knowledge in building stuff.

Then again, if I was doing this I would make it bigger and do the work myself after hiring a company to come out and tell me how it should be done.

This is what I am going to do when I buy My last house, I have seen it done and it looks amazing