There's lots of ways to do this but the cheapest I've found is this: Baking soda and/or a pinch (2 cap fulls/80gallons H2O) of hydrogen peroxide.
If you don't have a tank this large 1 cap full of hydro peroxide will be fine.
I clean my tank with baking soda every so often, but doesn't hurt to drop a little in after a water change either. That or the hydrogen peroxide. Both very cheap and prob more effective than other substances.
I've seen several topics come up on this and thought I'd throw this out there, may save you a little money.
Wax
Last edited by waxnslabs; 09-26-2013 at 02:11 PM.
Better yet if you got a couple of days put a bubbler in the tank and the chlorine will be gone in24hr. But I always give it a couple of days