Removing bulkhead

[pewter_jean]

I had taken my 50gal to a LFS on the IL side to have it drilled and bulkhead added to use this tank as a sump. Plans changed and I picked it up from the store so I could clean it up and sell it or use it for something else. While I was at this LFS picking up the tank I noticed the tubes of sealant he had lying around that he was useing to make some other sump for other customers. It was not aquarium sealant, it was kitchen and bath silicone, red and white tube from Home Depot. I don't know for certain he used this on my tank, but changes are good he did.
Now when I was getting the sealant for my sump Chad told my not to use anything but aquarium sealant, other stuff can leach stuff into the water. So now I want to take this silicone stuff off that the LFS used and replace it with aquarium sealant. How difficult is this? Can I just take a razor blade and cut the other stuff off. Or once it on that is it. Or should I not worry about it. I was going to try to sell this, and It wouldn't right to sell someone something that could cause them problem down the road.

[DrBDC]

You can use GE silicone I on aquariums. Same stuff w/o the word aquarium to drive the price up. You can't or rather shouldn't use the GE II but many have w/o problems but my preference would be to just avoid the whole issue and use GE I.

[latazyo]

anything that says 100% silicone is fine...sometimes the kitchen/bath business has anti mildew crap in it, that is the stuff to avoid

why dont you call and find out what he used?

chances are a guy that makes sumps and works on aquariums would know better and use proper silicone