One of my new tanks got cracked on the way over...it was free so no complaints. I was thinking maybe I could put some aquarium sealant on the inside and outside to patch it up. Has anyone tried this? The crack isn't all that big but it definatly won't hold water the way it is.

A lot depends on where the crack is and how big it is, etc. If a crack is on the bottom and goes multiple directions - it goes, then turns and goes again, you are probably not going to be able to repair it well enough that it will support the weight of the water. IF the crack is on the bottom or the bottom part of the tank there is less possibility to repair it. The top is easy.

I have had the best luck in repairing a tank when I use a tape with a strong fiber incorporated into it. Clean the tank glass very well - using alcohol or such to remove all grease or oil and other contaminants from the glass. Apply the tape across the crack with the fibers running 90 degrees to the crack. Make sure you cover the end of the crack. Then seal this over with sealant inside and out.

You can test your tank patch by filling the tank completely to the top with water and letting it sit for 24 hours. I place the tank on some pieces of dry newspaper, then fill it to the top. The newspaper will turn dark whereever water hits it and makes a leak very easy to see - even a very little leak.

Good luck. What a pain. I am sorry....

Got me Daryl i was going to post about the same thing

Thanks Daryl. I'll pick up some tape and sealant next time I go to the store. I'm pretty sure I know of some tape that would be perfect. The crack is towards the bottom though. It's kind of a parabola that opens towards the corner. There is also a crack a couple inches above the bigger one but it doesn't go all the way through the glass...its only on the outside but I imagine it will go the rest of the way through when I put water in it so I'll patch that one up to. It can't hurt to try at least . If it doesn't work I can always use the tank for something else...