How much sand to put in a pool filter can be determined by reading the manufacturer's label on the side of the filter tank or consulting a swimming pool professional. The amount of sand needed varies depending on the manufacturer and the size of the filter tank. Pool sand is usually changed every three to five years.
The roughness of filter sand makes it very efficient in filtering out dirt particles. Over time, the sand wears down and becomes smoother, and the filter loses efficiency. To change the sand, first the filter and pump must be turned off and the water drained from the filter tank. Remove the pipes or hoses to the filter valve, and then remove the valve itself. Before removing the sand, the open standpipe must be covered so sand doesn't fall into it. The old sand can be removed with an industrial shop vacuum or a plastic cup. Next, the tank and under-drain laterals should be thoroughly rinsed with a garden hose. Before adding the new sand, the tank should be half-filled with water. After the sand is poured in, fill the rest of the tank with water, and snugly replace the valve and hoses.
It is important to use only coarse filter sand and not any other type of sand. After changing the sand, the system should first be run in backwash mode to thoroughly clean the new sand, then it should be run on the rinse setting for one minute, and finally it can be set to filter the water normally.