Faulty Gauges and Sounding pipes : Most of the Ballast tank gauges work on pneumatic pressure difference method, where a measured pressure of air and difference of counter pressure gives the level of ballast in a tank and the reading is displayed in Cargo control room through a digital or analog reading. These gauges are to be purged regularly and readings should to be compared with manual soundings to eliminate erratic readings. Sounding pipes are often found choked with rags or sounding rods or tapes. They must be clear at all times to get correct manual soundings to ensure the tank is completely empty or intermediate readings are correct in case the gauges are faulty. This will prevent dry running of ballast pumps.