One of the most important things you can do is clean your pool filter. Turn on the filter, then leave it for between 2-5 days to clear the water. During this step, you may have to clean the filter multiple times. Pay attention to the pressure gauge. Clean the filter if it rises to 10 psi above normal. The filter cartridge will need to be removed and cleaned with a garden hose and spray nozzle. To get rid of all gunk, you can use a filter cleaner.