Double flush for free.

[Thomas]

I have a regular toilet about ten years old with 8 month old fluidmaster or similar guts. When I flush I get a 'regular' flush in about 4 to 5 seconds then another flush right after (without me doing the flush). The bowl fills, flushes, fills and flushes. When looking into the tank, it appears there is enough water left after the first flush to complete the second flush before the flapper falls. The tank level is the same as it was prior to this oddity. One odd thing is I can hear a gurgle flush through my bathtub as if there is a blockage but all drains go down quick with no backup. Any ideas on the cause of the mystery flush and a remedy?

[jamesgangnc]

It's a low flush toilet. Some one put a regular flapper in it. They normally have a flapper with a hole in the side and a foam float on the chain to the handle. This causes the flapper to close early. The design keeps the additional pressure from the top of a normal sized tank while reducing the flow by closing the flap early. The bowl is designed to flush with less water. Put the right flapper on it and it will be fine.