Add a few small stones or some sand to prevent movement during toilet flushing. Tank dams can make a toilet more water efficient. Bricks are not good inserts because they flake off inside the tank and interfere with proper sealing of the flush valve. If accidentally dropped while being inserted, a brick can break the tank. This reduces the pressure and velocity of the flushing action and may adversely affect performance.
Plastic bottles make good toilet tank inserts.
Trim containers to suitable height and add sand or stones for ballast Figure 2c. The float ball can be temporarily unthreaded from the float arm for placement of a large container. The float ball is reinstalled and inserts are ready for use. Some have maximum flow rates as high as 10 to 12 gpm. Waterconserving models are designed to provide a pleasant, well dispersed spray pattern at normal household pressures using only 2 to 3 gpm.