A step-by-step guide for those who want to D-I-Y instead of P-A-Y
Sand filters are the most common pool filter in America, and one of the easiest to operate. You have probably been loving your filter since it is efficient, inexpensive, and overall, fairly low maintenance. Unfortunately, filter sand must be replaced and is quite the labor-intensive undertaking to change out. You can pay a professional to change your pool filter sand, but you can also do-it-yourself if you have the right tools and the time to take on this project. If you have read about the signs your filter sand might need changed and you’re the kind of person who would rather D-I-Y instead of P-A-Y, follow this step-by-step guide below on how to change your pool filter’s sand.
STEP 1: GATHER THE EQUIPMENT AND PRODUCTS YOU’LL NEED
Equipment Needed:
- Shop-Vac
- Screwdriver
- Garden hose
- Flashlight
- Duct tape
- Utility knife
- Mask
- Backwash hose
Products Needed:
- New pool filter sand
- Replacement O-ring for multiport valve
- Silicone lubricant
- Pipe unions (if needed)
STEP 2: TURN OFF THE PUMPTurn off the filter and pump. Better yet, shut off the main power source to the system. If you have a pump timer, turn that off as well so that the pump won’t tun on while everything is disconnected. Should this happen while everything is dry, it could easily burn out.
STEP 3: DRAIN THE FILTER
If your filter has a drain plug, remove it from the filter tank to release the pressure and drain the water. Give the drain cap at the bottom of the tank just half a turn counterclockwise to let out all the air. After a burst of air pressure, remove the cap to drain out the water. Keep in mind this can take an hour or more, so plan accordingly and know you will have to wait a while for this step to complete.
STEP 4: REMOVE THE MULTIPORT VALVE
Remove the hoses that are connected to the multiport valve. Most hoses can be removed by loosening the clamp and pulling off the pool hose. Once hoses have been removed start opening the filter tank by either threading off the dial valve clamp or loosening the screws on the two-piece clamp assembly. This is where it gets tricky. You must loosen the dial valve from the center pipe of the lateral system. Do not pull the internal assembly up by the dial valve or it may cause damage to the laterals (fingers) located on the bottom of the filter. Wiggle the dial valve back and forth on the center pipe until the dial valve and center pipe come apart.
STEP 5: COVER STANDPIPE AND REMOVE OLD SAND
As soon as you remove the multiport valve, you will see an open standpipe inside the tank. Using duct tape, cover the end of the pipe to prevent any sand from falling into it and clogging the laterals. If it does, that sand will get flushed right into your pool when you start up the pump again.
Using your shop-vac, begin to suck out all the old sand from the filter tank. If you don’t have a shop-vac you can carefully scoop out the old sand with a plastic cup or bucket, but it will take a very long time. You will want to keep removing sand until the tops of the laterals are visible at the bottom of the tank.
STEP 6: REMOVE THE LATERAL ASSEMBLY AND PIPE
Fold the laterals up to the side of the pipe so that they clear the filter opening, then smoothly pull the pipe and lateral assembly out of the filter. Not all laterals fold up, therefore if you have laterals that thread or snap into the center hub of the internal assembly, unthread or twist each lateral out of the hub and remove from the tank. Use a flashlight to inspect if there are any breaks in the laterals or standpipe, and repair or replace as necessary to avoid sand from entering your pool. If the laterals appear clogged you can soak them in a bucket of cleaning solution for a few hours, then thoroughly rinse and reinstall them onto the assembly.
STEP 7: WASH THE TANK AND FILL HALFWAY WITH WATER
Use a garden hose to thoroughly clean the inside of the tank and remove any excess sand. Now that the filter is clean, replace the drain cap, reinstall center pipe and attached laterals or lower the laterals back into position. Fill the tank with enough fresh water to cover the laterals. This makes a cushion for the filter sand to prevent damage to the laterals.
STEP 8: ADD NEW SAND
Check again to see that the standpipe is taped off to prevent sand from entering and clogging the laterals and add more tape if needed. To protect yourself from breathing the sand dust, you may want to next put on a mask. Keeping the pipe centered in the tank, cut open a new bag of filer sand with sissors and carefully and slowly pour sand into the filter unit. Add one bag of sand at a time taking extra care to level the sand as you pour to make certain even sand distribution for efficient filtration and water flow. Also take note that it is very important not to lift the lateral assembly off the bottom of the tank as you pour in new sand as you will NOT be able to push it back down without rotating the laterals up – and upward-facing laterals do not properly filter your pool water. It is very important to use only the amount of sand that is recommended.
STEP 9: INSPECT (AND POSSIBLY REPLACE) THE O-RING
Remove the O-ring on the bottom of the Multiport valve and check it for wear. Since you only do this every several years, it’s probably a good idea to replace the O-ring even if it’s in decent shape as they are quite inexpensive. Whether you replace the O-ring or not, lightly lubricate the O-ring with a silicone lubricant and place it on the underside of the valve.
STEP 10: RECONNECT THE MULTIPORT VALVE
Remove the duct tape from the end of the standpipe and carefully place the multiport valve back into position on the pipe. Secure the valve clamps around the tank and tighten them into place. Reconnect the unions with the pool pump and the return ports. (If your filter doesn’t have unions, now is a good time to add them, or you can glue the pipes back together with straight couplers.)
STEP 11: BACKWASH THE FILTER
Attach the backwash hose and turn the multiport valve to the backwash position before restarting the system. Turn on the pump. Backwash the filter for at least two minutes to flush out the sand dust and extra debris from the new sand.
Once the backwash water runs clear and clean, turn the pool pump off. Switch the multiport valve to “Rinse,” then turn the pump back on. After about a minute, the water in the sight glass should be clear.
STEP 12: RUN THE FILTER
Shut the pump off, turn the valve to “FILTER”, and turn the pump back on. This is the normal operating mode for your filter! Note the pressure gauge reading. This is your filter’s clean sand filter pressure or “normal running pressure.” Remember it or write it down somewhere handy because when the pressure is 10 psi above normal, you will want to backwash the filter. Using the pressure gauge as a backwash indicator prevents you from over-backwashing and removing the dirt and debris your sand filter needs to function properly.
GIVE YOURSELF A SAND (OR HAND THAT IS)!
Changing the pool filter sand is a big job, but once the new sand is in and the pump is off and running, you’ll be back to the low-maintenance life! All you need to do is keep up on regular maintenance and backwashing so your filter will run at optimal efficiency until the next time you have to change the sand, and with that you can swim and float peacefully for the next 3-5 years!