Sorry, forget all I said. I was talking about a cold water storage tank. It wouldn't start complaining immediately the toilet was flushed. Hope my 'solution ' is helpful elsewhere.
A more adaptable option to a yogurt carton: Fill a small plastic sandwich bag with water and tie the neck so that little or no air is entrapped. Suspend this from the ball-cock arm with a non-rot non-rust 'string' so that it is fully submerged in the water. As the bag is almost weightless in water a...
