After a few years of normal operation your pool filter sand gets full of particles and debris that will cause your chemicals to not work as well as they normally should. Changing your sand is a simple process that should be done at least every 3-5 years to make sure your pool operates at 100%. here are the quick and easy steps to replacing your sand filter. Please note that these are generic directions for a unit with a removable, top mount valve. For the correct procedure for your filter, refer to the owners manual that came with your filter. 1. Turn off the pump, unscrew the drain plug on the bottom of the sand tank, and take off the Multi-Port Valve. 2. Take a wet/dry shop vacuum and suck out all the old water and sand. 3. Once all the sand is removed take a water hose and spray out any remaining debris that is left in the tank (be cautious to not break the plastic laterals that are in the bottom of your tank when vacuuming). 4. Put back on the drain cap for the sand filter. 5. Fill your tank at least half way up with water (this helps the sand settle down easily without breaking the plastic laterals). 6. The type of sand that you add to the filter will be #20 silica sand which is specifically produced for filter media. This sand is between 40-50mm in diameter and is available from most swimming pool supply stores. Do not substitute other types of sand or you will almost certainly have problems with your filter and potentially damage the pool also. 7. The amount of sand that you add to the filter will depend on the size of filter that yo have. You must be certain to find accurate information about how much sand to use in your filter. Over filling or underselling the filter will at least cause the filter to not function properly, and worst cause damage to the filter. Filter sand sizes range typically from 100 or 150lbs all the way up to 600lbs or more for large pools. 8. Be sure not to get any sand into the sandpipe which will be wide open. It is difficult to get the sand actually into the filter without getting it in the sandpipe so you may like to tape up the standpipe opening to prevent this spilled sand from making it back to the pool through the return lines. Also, be sure that the sandpipe is aligned in the center of the tank during the process of adding the sand. Failure to do so will cause you to have problems putting the multi-port valve back on the tank. 9. Gently pour the sand into the filter. Failure to fill the tank at least half full of water and/or dumping the sand in too roughly can break the laterals in the bottom of the tank. 10. Once the sand tank is filled with the required amount of sand, you can put the MPV back on. Make sure the MPV is tight and secure (do not over tighten). 11. Once back together the first thing you need to do is give the filter a thorough backwash. You should start this process by over filling the pool and then backwashing for as much as 3 to 5 minutes, followed by a 60 second rinse cycle before setting to "filter). If you have any questions about the process of changing your sand, please make sure to contact your pool professional.