Bests & Worsts Reviews from Amazon

I have a new-ish American Standard toilet (1.6 gallons per flush) with a 2" flapper that was misbehaving. I've done my share of household plumbing, installed several toilets, and have replaced the fill valves on multiple toilets many times. I replaced the OEM flapper with with this Fluidmaster flapper since it was advertised to be adjustable from 1.6 gallons to 3.5 gallons. What a disappointment! First, and most importantly, it does NOT provide a 1.6 gallon flush regardless of the setting. Every setting results in the tank completely emptying. I adjusted it across it's entire range with many, MANY flushes while watching the flapper. It comes up, stays up, and does not drop back down until the flapper is almost completely out of the water. If that weren't enough, it also has the following design flaws: the plastic bracket that holds the actual rubber flapper has a cutout in it with sharp corners right below the point where the chain attaches. This is perfect for catching the chain when the flapper is in the upright "flushing" position. Then when the flapper goes to drop down, it stays open because the chain is caught in this little notch. It does this about 30% of the time, requiring jiggling the handle to free the chain and let the flapper close. Also, the underside of the flapper - the flat part that forms the seal - does not always seal well. I've never seen another flapper with this problem. There is something about the shape of the bulb on the bottom or the flap that sometimes lets the flapper come down misaligned, leaving a gap through which water will leak. Again, jiggling the handle is required to get it to properly seal. This may be partially caused by the fact that it always empties the tank so there is very little water pressure to push the flapper into a solid position. It's as if the designers deliberately went out of their way to make a poor product. Save yourself frustration and get an OEM flapper or a regular non-adjustable one.