leak in sump
 

I bought a 75 gallon to use as a sump and the prevous owners say that there is a leak somewhere. Can I just reseal the whole tank with silicone (put it over the existing silicone) or do I need to find the leak?

Take a razor blade and cut out the existing inside corner beads. Then if you can find some GE SCS1200, run in new beads about 1/4" in size and you will be good to go.

hey grizz, is the GE SCS1200 that much better than the regular stuff? About to reseal a couple tanks myself just need to go grab some silicone one of these days to get started.

sorry for the hijack heh

MUCH MUCH BETTER, it is what all good reliable tank builders are using. It has a much higher tensile strength because it is a construction grade. It is also, IMO, much nicer to work with.

Edit: if you are unable to locate it, drop me a PM.

Why not put some water in the tank first to see if the leak is obvious, then you can concentrate your efforts in the area that needs it rather than removing a bunch of silicone without knowing?

He he, edit, just noticed you're in Cold Lake, cool pool... I spent a few years up there myself.

The only issue I had with doing exact thing is, one of the small tanks I had kicking around waiting to be a sump had a small leak as well. I filled it and let it sit for a day on saw horses so I could see almost every inch of it. I thought I found the leak, touched up the silicone in the area, let it set & filled it back up. Only to find out that it still leaked. So I decided to start cutting away the old silicone & low & behold the leak was on the otherwise of the tank completely. For the time it takes to peel out the old stuff and put in new, time well spent. Just my 2 pennies & experience.

I've done the same thing with patching a leak. generally if it's leaking in one spot, others will quickly follow. I thought that resealing a whole tank would be a pain, but it was surprisingly easy. I probably spent more time screwing around with the leak than i did resealing the tank.

I resealed my 75g sump in about an hour. Also, if you're just doing the corners to seal, strength isn't really an issue, so any (pure) silicone will work fine. The GE 1200 is stronger and recommended for assembling the glass.