Empty the current sand. This can be accomplished by spreading a tarp or plastic sheet under the filter drain assembly and take the entire assembly off. Turn on the pump and this should remove most of the sand through. Another way of doing this is let the filter drain a period of time. (Could be a few hours or a few days) Gain access to the sand by removing the multiport valve and removing the dome.
You may have to cut some pipes (you can reconnect later with couplings) to remove the valve if you have a top mount multiport. Remove the clamp band binding the valve and filter. The valve now will come right off. Using a small cup remove the sand inside the filter making sure you have covered the standpipe with tape so sand does not get spilled into it.
It is recommended to replace the laterals at the bottom of the tank when you replace sand. This is due to the tendency to become brittle with age. If not replacing, care must be taken so you do not hit them in the process. Use a hose wash out sand that is under these laterals. Using a silicone sealant on the drain assembly threads, replace the assembly after sand has been removed from the tank. Cover the laterals with water so they are not cracked with the new sand. While adding the new sand if you have a top mounted multiport, cover the stand pipe so that sand does not enter it. Wrap the baffle with plastic or move the intake gently on a side mounted pool filter valve, again to prevent sand from entering into it.
Using 45-55mm diameter #20 silica sand, you now start adding sand back in. We recommend having someone hold the stand pipe in position at this point. In the case of a top mounted multiport pool filter be sure that the hub assembly remains in the center.
Upon completion of refilling, replace the lid securely. To make sure you do not overfill with sand, call us and will be happy to help.
To prevent sand dust from getting into your pool, if you have a push-pull valve back wash first after replacing the sand. If you have a multiport valve, start up on RINSE mode when you restart the filter.