How to Change The Sand in Your Pool Filter

Have you ever wondered if you need to do anything with the sand in your pool filter? In this article, we’re going to look at pool filter sand.

First, we answer the question, “Why change pool filter sand?” Then, we look at how to change the sand in your pool filter.

Why You Should Change Your Pool Filter Sand

Sand filters are common in Oklahoma, and if your pool uses a sand filter, here’s why you should change it:

  • Your old sand has round edges that don’t filter water well.
  • New sand has sharp,  crisp edges that stack and filter water better.
  • With each backwashing, you push dirt, dead algae and residues into the sand bed.
  • Small amounts of sand can be lost over time.

When Should You Change It?

If your pool is chlorine, you’ll want to change the sand every 5-6 years, unless you are having problems.

We also recommend chemically cleaning the sand once to twice a year. You can stop by one of our two locations for more information on this.

If you are using Baquacil, we recommend changing the sand yearly.

Over time, the sand inside the filter loses its coarseness and becomes smooth and round. This makes it very hard for the sand to catch really small debris particles. Sand is like a fine wine, it gets better with age, but then has its peak, and it’s all downhill from there. Unlike wine, this time period is very short.

You definitely want to change the sand if the quality of your water is poor or you notice short filter cycles (the time between backwashes) or dirt is passing through the filter.

Can I Use Any Sand?

No. You want to use Pool Filter Sand. It’s often labeled as #20 Silica sand.  The best place to buy it is from a pool dealer (Us!) because the quality of your sand makes a difference.

How Do I Change the Sand?

You’ll need a few items:

  • Shop Vac
  • Screwdriver
  • Pool Filter Sand
  • Duct Tape or Rubber Plug

1. Turn Off The Pump And Drain The Filter

Turn off the filter and pump. 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 Multi-port Valve

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

Remove the clamp or collar that holds the valve to the tankYou 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 multi-port 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.

SMART TIP: Use a shop vac to make the job faster and 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 sand. Broken and cracked laterals 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 cushions the fall of the sand onto the laterals which will protect them from breaking.

7. Add The New Sand

Sand is heavy. Set  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. Use the sand from Fiesta Pools and Spas.

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 multi-port 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 multi-port 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 helps get out all of the sand dust and extra debris in the new sand.

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

If you have a Baquacil pool, we’ve got Backwash Filter Cleaner. Run this once a month to stay on top of chemically cleaning the sand. Since Baquacil filters out twice the debris as chlorine, you want to maintain it more often for best results.

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.

Not sure you want to get involved with changing the sand in your sand filter? We can help! Contact our highly trained and experienced Service Staff to help!

Image: David Heib

Reference: Swim University