My tank started leaking tonight. It is ever so slow - a small drop every 10 seconds. It had some sort of putty placed over it, which was accidently scraped off when I moved the tank. I have no idea what to use, but I'd like a similar substance I can pick up cheap tomorrow from a Hardware. Can anybody recommend what to use? Can I apply it straight over the tank as it is, sitting in place and with the leak constantly happening?