How-To Change the Sand in a Sand Filter

Thanks to Swim University for these great tips!

Every 3 to 5 years the sand in your sand filter needs to be changed. Over time, the sand inside the filter looses its coarseness and becomes smooth and round, making it very difficult for the sand to catch small debris particles.

You’ll need:

  • Shop Vac or large cup that will fit inside the filter
  • A screwdriver
  • Pool filter sand (check your filter’s manual for the amount)
  • Duct tape or rubber plug

1. Turn Off The Pump And Drain The Filter

Turn off the filter and pump, and make sure your timer isn’t set to turn back on. You don’t want the pump to kick on while you have everything disconnected. If the pump runs dry, it can burn out.

Remove the drain plug from the bottom of the filter tank and let all the water drain out. This may take a while, so you can do this ahead of time.

2. Remove The Multiport Valve

Remove the hoses or pipes that are connected to your valve. If your valve is hard plumbed with PVC pipe, you will have to cut the pipe and install union fittings so that you can easily change the sand in the future.

Remove the clamp or collar that holds the valve to the tank. You may need your screwdriver for this task.

Once the collar and pipes or hoses are removed and disconnected, gently twist and pull up on the multiport valve to remove it.

NOTE: The valve is attached to a standpipe that runs into the sand. At the bottom of the standpipe there are laterals that spread out along the bottom. Try not to twist too hard because the laterals could break under the weight of the sand.

3. Cover The Standpipe

Inside you’ll see the standpipe that leads down into a large pile of old filter sand. Before you remove and add the new sand, you need to cover the top of the pipe. You don’t want sand getting inside the pipe, because when you finally finish and turn it on, that sand will end up in your swimming pool.

4. Remove The Sand

Remove all the sand by using your industrial shop vac or a large cup and scoop out all the filter sand.

PRO TIP: I suggest using a shop vac, it makes the job faster and much easier.

5. Rinse Out The Tank and Laterals

Now you should see that the filter standpipe has a number of laterals sticking out of it. Use your hose and rinse out the rest of the filter sand.

Take this time to check the pipe and laterals for any cracks or other damages. If the pipe or laterals are broken or cracked, replace them right away before adding the new stand. Broken and cracked laterals will cause sand to end up in your pool.

6. Fill The Tank Halfway With Water

Before we add the new sand to the filter, set the standpipe and laterals in place and centered, replace the drain plug on the tank, and fill it halfway full of water. This will cushion the fall of the sand onto the laterals which will protect them from breaking.

7. Add The New Sand

Remember, you are working with heavy bags of sand. I suggest to place one bag at a time upright near the top and cut the bag open, letting the sand slowly pour into the filter.

Depending on the size of your filter tank, you may have to do this several times.Remember, just take your time to prevent sand from spilling everywhere. And make sure that standpipe is covered.

NOTE: Only use filter sand! There are different types of sand out there including bar sand and play sand, but only your local pool company offers the correct coarse filter sand or filter sand substitute.

8. Fill The Tank With Water To The Top

Once all of the sand is in your filter, fill the rest of the filter up with water.

Replace the multiport valve, collar, and pipes or hoses securely and tight.

9. Backwash and Rinse The Filter

Before you turn your filter and pump on, turn your multiport valve to Backwash. Prime your pump and turn it on. Let the filter backwash for at least 2 minutes or until the sight glass is running clear. This will help to get out all of the sand dust and extra debris in the new sand.

Afterwards, shut off your pump, turn your multiport valve to Rinse, and turn your pump back on. Rinse the filter for about 1 minute.

10. Run The Filter

Great! You are all finished. Shut off your pump, turn it to Filter, and turn your pump back on.

Check the pressure gauge. Whatever the gauge says should be your normal running pressure. Keep an eye on this. When the pressure goes to about 10 psi over the normal running pressure, you need to backwash the filter. Over backwashing gets rid of the dirt and debris that will actually help pick up new, smaller debris particles. Don’t over backwash. Use the pressure gauge as your backwash indicator.


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