The pool filter is the heart of your swimming hole. If it is working properly, the water stays clean and crystal clear. To keep the filter operating at its optimum, you need to replace the filter media. Your system will likely fall into one of three categories: sand, diatomaceous earth (DE) or cartridge.
Replacing a Filter Cartridge
If your filter system uses cartridges, you will need to replace it approximately every two weeks, on average. Place a stopper at the intake and return ports on the pool before opening the filter. The plugs stop the gravity flow of water into the filter while you change the filter cartridge. Unscrew the cover of the cartridge chamber. Remove the used cartridge. Install a new cartridge. Replace the cover and tighten the screw. Remove the stoppers from the intake and return ports. If available on your filter model, open the air release valve until water flows through.
Replacing Filter Sand
Replace filter sand every three to five years to keep your system operating at optimum. Plug the intakes in an above-ground pool to keep the water from flowing into the filter system. Generally speaking, filter systems are placed above the water level of in-ground pools, so plugs are not necessary. Open the filter drain valve to remove all water from the filter tank. Scoop the sand from the filter tank. If the opening is narrow, use a wet/dry vacuum to lift out the sand. Inspect the inner parts of the filter system, such as the standpipe and laterals, if so equipped. Replace worn or broken parts before filling with sand. Consult the manufacturer’s recommendations for the correct quantity of sand for your system.
Replacing Diatomaceous Earth
Replace diatomaceous earth (DE) with every filter backwash. When you notice the pressure gauge reading 10 psi higher than normal, it is time to flush the system of dirt and debris built up inside the filter unit, which will remove the DE as well. Shut off the electric pump. Move the pump handle down slowly, then up briskly eight times. Close the intake and return valves. Open the filter drain to allow built up dirt, debris and used DE to flow out of the system. Close the filter drain and open the intake and return valves. Turn on the pump. Add the quantity of DE as per the manufacturer’s instructions, through the intake skimmer.
Unplug or disconnect the electricity going to the pump before replacing the filter media. Turning off the electricity removes the risk of an electrical shock. Also, if the pump turns on with no water in the system, the motor can burn out, leading to a costly repair.
Use caution when opening a sand or DE filter. A buildup of pressure inside the filter tank can cause an explosion of water and filter media. Keep your face protected and wear goggles.