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i was wondering what would cause a 100 gallon glass tank to get a hair-line crack on the bottom of the tank. the crack goes all the way to the width of the tank.

the tank and stand was on a carpet, which was level. its on the ground floor (if it matters). the tank and stand was level. when i talked to the LFS, they said it must have been the carpet. does anyone know the cause of the crack? what can i do to prevent another broken tank?

was it an old tank? how thick was the styrofoam you had it on? was the stand level and perfectly stable without the tank on it? was it still level when filled? I have had problems with my 145g because the floor is a bit old in my house and in that particular room the floor is terible, The tank warped a few floor boards and i had to put the legs on flat peices of wood to disperce the weight a bit.

[This message has been edited by Qserv (edited 02-18-2002).]

How thick is the bottom?
Being a 100g I would imagine 10mm
did you use foam to absorb any slightly uneveness?
Does the crack go all the way through the thickness of the glass?
can you show me a photo of it.

Sometimes when a tank isnt assembled dead set square it cause stress on the bottom of the tank, causing it to eventually crack.

If the crack is clean and goes from front to back then a large peice of 8 to 10mm glass sealed over it on the inside will fix the leak and reinforce the bottom.

This will save having to replace the bottom.

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TONY
Australian and proud of it!!
My Cichlidfish.com Home page

unfortunatly, i didnt have any foam under it.

qserv:
it was a new tank..brought it on oct 2001, filled it by dec 2001.

the stand was level....what do you mean by stable?

yes the take was level when it was filled
just to be sure that we're on the same page here, the stand doesnt have legs, but is just 1 whole piece.

oscar2001:
what do you mean by how thick is the bottom?

the tank's crack goes all the way through.

and yes i can show u a pic, bad quality, but hope it'll do.

o yah, i sealed the crack with that 100% silicone already. i doubt it'll work, but gotta give it a try.

thanx for all ur responces

No foam would most likely have caused it, The foam lets the tank sit evenly dispercing the weight across its surface as the tank sinks into it, no stand would be 100% flat or 100% level, without the styro 1 small raised section could cause the tank to to crack due most of the weight in that one area i.e 100gallon tank weighs something like 500-600 kg full of water and gravel etc, also maybe the stand is slightly warped,, you may want to check it out along the whole surface with a spirit level.

Its probobly would be a good idea to remove the silicon you put in the crack or aleast smooth it out level with the glass so you can put a peice in like Tony has suggested. I wouldnt fill it with just silicon in/over the crack. I have repaired a tank in the same way tony has suggested and it worked great,, but it was only a 40g out of 6mm glass.

[This message has been edited by Qserv (edited 02-18-2002).]

I would agree that it was probably the lack of foam that caused the split... even something as small as a grain of sand could cause enough preasure when the tank was full to cause a crack...

It is also possible that it was a manufacturer's defect and that you didnt do anything wrong... btw carpet under the stand will not cause a tank to split that was the LFS's way of blowing you off, just so you know. If it is a name brand tank like "All Glass" or "Oceanic" etc etc they usually have a 2-5 year warranty against defects... if that is the case I would get in touch with them and they might just replace it for you.

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Adam

Come see my website!
Adam@cichlidfish.com
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Sorry DM
No Foam says it all, especially with a tank that big.
Thickness of the bottom glass is normally a few more mm`s than the rest of the tank and the thicker the glass the better chance of repair.
Yeah the silicon alone wont hold the pressure and plating or replacing the bottom are your real only choices. Id go for plating first as I have had a lot of success with this method and its covered by gravel so you cant tell once its setup.

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TONY
Australian and proud of it!!
My Cichlidfish.com Home page

damm... so how does one plate the tank?

should i take out the silicone stuff?

its probably the foam, but i brought the tank when there was a huge fish convention thing out. they were selling 10 gallons for 99 cents. when i got the tank, that damm thing was so poorly made. cracked after a month. anyways, thanx for the advice..what should i do now? anyway to save the tank?

You could always switch your beardies to the 100 since you dont have to worry about it leaking... and get your arowana just a thought.

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Adam

Come see my website!
Adam@cichlidfish.com
Got ?'s about HITH? Read this to learn more!

Remove the silicone you have placed on the crack and thoroughly clean the area with methylated spirits (Takes time so dont rush the job)Get a 10mm plate of glass cut so it just fits"flat" in width way(front to back) and is a foot or so long. Put "fresh" silicon over the crack and in several diagonal lines and on the "bottom" edges of the plate. Place the plate over the crack, gently squeezing down the plate. Wet your finger and gently run it around the edge of the plate to smooth out the silicone making it water tight. If neccessary run a bead of silicone around the plate if it apears to lacking.
Place a couple of bricks or simular over the plate and wait 48 hours then test for leaks(with thick foam under the tank } and fix with more silicone if neccessary.

When working with the silicone you have to do it a resonable pace before it starts to cure.

Cleaning the area is vital to a successfull repair so dont skimp on it by not removing all the old silicone above the crack

adam: yah, i would love to do that. especially get two jobs done with out work . unfortunatly, the 180 got some small cracks everywhere so thats out. maybe in the near future i can try to find them and repair them. ahh yes, still havent forgot about my aro eh i still see it in the shop swimmin in that lil tank.

Foam under big tanks? Nobody ever mentioned that to me. Under the tank stand I do run 2x4's along the floor is that kind of doingthe same thing.

If I have to empty my 125 (again) Im going to blame it aall on you guys

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Candice

Hi C4, you should always have a peice of styrofoam or something between your tank and stand to settle the weight evenly, all my tanks have foam, even my 2ft. I use 14mm styro under my large tanks.

Mick.

I have never heard of the foam thing either. What size thickness and where is the foam placed???

Yea whats with the foam?
Are you telling me my new 90gal is gonna break?

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