It will leech a little over time in the tank, but its nothing to worry about, it usually clears up with water changes. Doesnt effect the fish in anyway, with lots of pieces in the tank it can lower the ph slightly but again nothing to worry about. When your ready to set up the tank, just pop it in.
If you already have tanks cycled, you can always use some filter media (sponge or bio balls) to help seed the new tank, will take much less time with mature media. You can safely remove 1/3 mature media (obviously replace it in the tank already running) to get the cycle going.
If you already have tanks cycled, you can always use some filter media (sponge or bio balls) to help seed the new tank, will take much less time with mature media. You can safely remove 1/3 mature media (obviously replace it in the tank already running) to get the cycle going.