The tank is a resevoir for the water from the pump. The smaller it is the faster it will "run out of water" and then the pump will start. THere is no direct relationship between the tank and anything else. A small tank will cause frequent short operations of the pump. A large tank will turn the pump on less frequently, and once it starts it will run for a longer period of time. The ideal solution is to install a larger tank if you have room for it.