okay - we have a crane toliet. the overfill tube assembly broke, so we went to home depot and bought a fluidmaster replacement kit, which included a new flap. Everything worked fine for a couple of months until recently. We are slowly losing water in the tank (I marked where it was after a flush and would check back later and the water level was down). This causes the toliet to run and replace the lost water. So, from everything I read, it has been suggested to replace the flap. Went to home depot and bought another fluidmaster flap. Still having the same problem. Is there anything else I should be doing or looking at? Is there a way to create a better seal between the flap and the bottom of the tank? Thanks!