Hi, I have the most useless concealed cistern in the downstairs toilet, the low flush barely dilutes the colour of wee and the full flush often needs two goes for anything solid! It is a Fluidmaster and a call to them having done all the usual checks resulted in tacit agreement because the staff member had the same unit. The pan is a modern one fitted at the same time. I asked if there was a way to convert the button to single flush to save the need to tell guests to go for a full flush the first time, but it seems not. I wonder if fitting a flap valve with a push button is likely to give any significant improvement. Any ideas please?