Need URGENT/FAST advice before purchase (chipped glass)...

[Buckdog]

I got a 120 also. Looking at the chip I would be skeptical. There is a post here or in "Aquaria Central" (sister site) I believe in "Lessons Learned" where a guy's big tank failed. He heard it all the way upstairs. The failure occurred roughly in the same place your chip is.
That is a lot of water resting at that point. If you dont know the history of the tank it may be a serious risk.

 

[Plecos_Ftw]

sorry to hear but Im sure things happen for a reason. and definatly keep your eye out on craigslist thats how we found a 75g

 

[bmxer4ever]

I think you did the right thing on a tank that size. Too much uncertainty.
I picked up a "freebie" 30x18x12 at the end of last year, got it home and discovered that the bottom back left corner hadn't just been chipped - it looked like it had crumbled!
Trouble was, it came with 24 small Convicts and all the kit, and I'd bagged half the water so suddenly I had a complete set up with a tank I couldn't trust!
Stuck everything in a 10 gallon plastic tub overnight, next day went out and bought a replacement tank (only £22) and water tested the suspect one for a week. It held water no problem, but I still couldn't trust it.
My solution? Siliconed a glass marble INSIDE the crumbled corner so that all 3 sheets of glass were bonded to the marble and filled the whole corner around it with silicone to completely seal it off over the top of the marble. Held water happily for the last 8 months and now holds ten baby Cons from the original 24 (traded in to lfs for over £50..!)......

This pic shows the repaired tank on the bottom of the stand before I swapped the Cons into it last weekend.