Before you assume the tank is leaking, check all the equipment to make sure it's not splashing or that water is getting out through the equipment somehow (leaking connections, filter, overflow, etc.). Also check the top seam of the tank, as those sometimes leak a little.
If one of the seams on the tank is leaking, it won't be long before the rest of the seam breaks and you have water all over the floor.
If it is the tank, get a new one ASAP. If you transfer everything from one tank to another, there shouldn't be a problem with the cycle.