# Help! Tank bottom cracked :(



## Geoff70 (Nov 26, 2009)

Got a really nice 2nd hand 3ft tank on Saturday, have been cycling it since (it's on a built in recess in the wall, perfect fit), just went downstairs by chance and saw water trickling down from the tank. Hurriedly emptied it of everything and found a crack right across the middle of the bottom, from front to back. 

Question is, if sealant is applied, will it withstand future pressure? As well as the volume of water (22 gallons), there were also a couple of quite large rocks and some pretty heavy slate pieces. One thing I didn't do (because I didn't find out until after I'd filled it) was to add a polystyrene layer underneath the tank (which I will do for sure next time! incidentally, how thick does this need to be?). I was lucky I hadn't added my live plants yet at least, let alone fish. It's for tropical community by the way.

Any advice greatly appreciated :notworthy:


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## dyzan8 (Nov 16, 2009)

22 gallons is a lot of water if it spills. I would personally not risk it both for the damage to your property if that breaks fully and for the live stock inside. I had a leak a few months ago - it came out no more than a little spurt - but in 24 hours it had ruined the floor around it and the ceiling below. I probably only lost a few gallons of water as well.


no good to you now but before you fill a fish tank new or otherwise its recommened you fill them up in a in a place (outside, in the bath etc) and check for leaks.


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## Geoff70 (Nov 26, 2009)

Well to make it clear, the tank was absolutely water tight when I got it, it was full from Saturday evening to this afternoon, when it started leaking - the problem was the lack of polystyrene sheet I'm sure.


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## dragonsnake (Jan 17, 2010)

if the crack is more than a 3rd of tank area the best you can hope to do is get a new piece of glass (the same size as the whole cracked bottom and replace it) but to be honest i would never trust a cracked tank especially if it's in a recess and as for undersheet 1/4" is plenty 

can you post a pic of the damage ?? would you not feel better selling the tank you have as a viv or rodent tank and getting another sorry but if it goes whilst stocked :gasp:


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## Luca Brasi (Feb 7, 2010)

Geoff70 said:


> Well to make it clear, the tank was absolutely water tight when I got it, it was full from Saturday evening to this afternoon, when it started leaking - the problem was the lack of polystyrene sheet I'm sure.


I'd tend to agree. Surfaces that look even to us, probably are not and this can put the tank under stress causing stress. You could silicone it together, but I'd only do this if the crack is a minor one. The silicone needs 48 hours to cure. After that time I'd add an inch or two of water and test it for a few days. And stick it on polystyrene! 

P.S Back in the old days, filling a tank and leaving it for a whole week to check their were no cracks was the done thing!


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## Marinam2 (Sep 4, 2007)

I wouldnt risk it!!


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## Luca Brasi (Feb 7, 2010)

dragonsnake said:


> if the crack is more than a 3rd of tank area the best you can hope to do is get a new piece of glass


Nah, you can fix some up easy. I've done it loads of times with sumps and fry rearing tanks without any problems.

LB


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## _simon_ (Nov 27, 2007)

You got off lightly, I've had a 100 gallon tank crack and empty itself in the lounge over night. Now that was fun to come down to in the morning!

For a 3ft I'd probably cut the bottom glass out and get a new piece cut. I wouldn't just try and seal the crack.


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## Caz (May 24, 2007)

You can fit a new bottom over the craked base but will need to razor blade the old silicone off around the edges to get a good seal/fix between new and old glass. Effectively a double base. Easy fix but think about why it cracked - some undo pressure from below probably. Is it sitting on 1" polystyrene?

Other option is to cut of the old base with stanley blade, clean up as above with meths and razor blade and silicone the new base glass on.

Both the above are no where near as difficult as they sound BTW.


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## cbarnes1987 (Feb 2, 2010)

do not risk, i had a slow drip in 1 corner, eptied and resealed, filled again an leaked again. would rather get a new tank than a new carpet


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## _simon_ (Nov 27, 2007)

cbarnes1987 said:


> do not risk, i had a slow drip in 1 corner, eptied and resealed, filled again an leaked again. would rather get a new tank than a new carpet


Sounds like either the area wasn't cleaned fully before you resealed or the silicone hadn't set. There's no reason why a home repair won't work. It's no different to buying a new tank.


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## Trillian (Jul 14, 2008)

cbarnes1987 said:


> do not risk, i had a slow drip in 1 corner, eptied and resealed, filled again an leaked again.


Ditto. Two of my tanks have leaked twice despite being resealed...:roll:...so I just ended up replacing them. : victory:


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## Luca Brasi (Feb 7, 2010)

If they've leaked since a repair then the repair wasn't carried out correctly. This is easy to check with a little patience just by adding an inch or two of water and leaving it a while (Not outside in freezing cold temperatures!). 

Honestly, it really does work. I worked in an LFS where cracked tanks were not uncommon and simply fixed up and used in a backroom quarantine / hospital section. No problems at all so long as it's done properly. This isn't a dig by the way.


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## Trillian (Jul 14, 2008)

Luca Brasi said:


> If they've leaked since a repair then the repair wasn't carried out correctly. This is easy to check with a little patience just by adding an inch or two of water and leaving it a while


That's what I did. I emptied the tank, let it dry out for a couple of days, applied a good dose of sealant, let it cure for 48 hours, then added a couple of inches of water, let it stand for a few days to check it was watertight...it appeared to be fine. Then, I refilled the tank, put all the gravel, decor, fish back and gah! 24 hours later...it leaked again! :bash:


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## Geoff70 (Nov 26, 2009)

Well to update, I found a guy near me who has just started advertising tank repairs on Aquarist Classifieds, so decided to give it a go. He said he's done it for himself before with no problems (he has 10 tanks), and for a few others, and has seen a gap in the market (there are after all lots of cheap tanks in need of repair on various classified sites). 

He covered the crack with a cut to fit piece of perspex, sealed in place with aquaseal. It's not the most aesthetically pleasing job, but as I said to him, how it looks is not high on my list of priorities - it will be covered with substrate anyway.

He said to leave it 24 hours then test it, and if there's a problem he would come back (looking at it I don't think there will be though, fingers crossed). Really friendly bloke, very knowledgeable (kept and bred for 20 years+). If anyone would like his number PM me.

I now of course have invested in a 1.5inch thick piece of polystyrene (JBL or something like that) from B&Q's roofing section; a bit galling that I could have saved myself all this hassle for the princely sum of £1.48! If only Dick Mills had mentioned the need for a poly base in his book 
Further updates to follow.


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## dyzan8 (Nov 16, 2009)

Good luck with it. Should be ok seeing as he knows what he is doing!


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## Geoff70 (Nov 26, 2009)

:2thumb:


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