Would the ajustable type flapper from Fluidmaster solve my problem?
Before replacing this flapper double check the mounts to make sure that they are not binding on the posts. Also check the flush handle to make sure it is properly returning to the at rest position then check the chain to make sure it is adjusted correctly. The chain should have bout two links of slack when the flapper is down and the flush handle is in the at rest position. If the chain is too long it will get sucked into the flush valve as the water discharges then it prevents the flapper from properly sealing.
