How to Change Sand in a Pool Filter

You probably chose a sand filter for your pool because it’s low-maintenance. Sand filters rarely clog up, they’re budget-friendly, and they do a good job of filtering your pool water. The sand in the filter only needs to be changed every 5 to 7 years, and you can enjoy crystal clear pool water the rest of the time. But how do you change the sand in the filter when it’s time?

Maybe you’ve never changed it before, or maybe it’s just been long enough since the last time you changed it that you’ve forgotten how. Either way, we’ve got your back.

This article will walk you through how to know it’s time to change your filter sand, help you decide what type of sand to use, and finally, how to change the sand when it’s time.

How to Change Sand in a Pool Filter

What is pool filter sand?

Your pool filter traps things like dead bugs, leaves, hair, algae, and bacteria, so they don’t stick around in your pool water. Unfortunately, this is the stuff that either leaves you with yucky, cloudy pool water or, at worst, makes swimmers sick.

So, it’s important that your filter system is working efficiently. The media in your filter is what snatches contaminants out of your water. For example, if you have a sand filter, sand is the filter media. It’s so effective that it’s not only used as a filter media in swimming pools but also wastewater, septic systems, and for drinking water.

If you don’t know what you’re looking for, all sand looks the same, so it’s tempting to replace your filter sand with any old sand. But don’t be fooled. Buying a bag of play sand at the hardware store will ruin your pool’s filtration system.

There’s more to sand than meets the eye, and there are three types of filter sand that you can use in your pool filter.

  • Silica sand
  • Silica sand is the most popular choice for filter sand in swimming pools, and specifically, it’s called #20 silica sand. This sand is derived from ground quartz, creating sharp, jagged edges on the sand grains that are especially good at trapping small particulates out of the water passing through the filter.
  • Silica sand is all-natural, as it is mined, not manufactured.
  • Glass sand
  • If you are looking for an environmentally-friendly sand option, glass sand is a good alternative to silica sand. Smooth to touch and made from recycled glass, it can still filter out incredibly small particles from your pool water.
  • Because the grains of sand are not uniform in size, glass sand is good at preventing channeling in your filter. Channeling happens when your pool water “cuts a path” through the sand and particles manage to slip through the filter. If you have hard water, glass sand is extra-helpful. Due to its negatively charged nature, glass sand captures manganese and iron particles, the elements that cause hard water damage to pool parts.
  • Zeolite sand
  • Zeolites come from volcanic rock minerals and have 100 times the surface area of regular pool filter sand. While you can’t see it with the naked eye, zeolite sand particles have a honeycomb shape that acts like a sponge.
  • Chlorine by-product chloramines are trapped by zeolite, so you can prevent some of the eye-burning effects of chlorine sanitization. In addition, this sand can help balance out your chemical availability if you find you’re having to frequently shock your pool.

Why do you need to change your pool sand?

Contaminants get trapped in your pool sand when water is pulled through the filter. This is the exact purpose of the sand inside the filter. While you can’t see it, sand particles have rough surfaces that contaminants bind to.

Over time, all your sand particles become “clogged” with contaminants and turn into smooth particles. This renders them ineffective at filtering your water. It’s the exact same process of weathering that you see on river rocks or beach sand that is constantly exposed to water flow.

Once your pool filter sand has been weathered smooth, it no longer binds to the contaminants in your water. If you notice your water becoming cloudy or that you frequently have to shock it, it may be time to change your sand.

How to know it’s time to change your filter’s sand

The lifespan of your filter sand will depend on what type of water you have in your pool, as well as how often your pool is used. It can range anywhere from 3 to 7 years.

Families with children often find themselves changing the sand more often, as the sand is exposed to more contaminants. But the timeline is not universal for changing sand.

The rule of thumb is that once your water quality starts suffering, it’s time to change the sand in your filter.

Can I just backwash my sand filter?

If the pressure in your filter system is too high (above 10 PSI), you will need to backwash it. If the chemistry of your water is ok, but it just has a slightly cloudy appearance, backwashing can help in this case, too.

The process of backwashing your filter will help to rinse the sand in your filter. In addition, it can be done as part of routine maintenance to make your sand last longer.

You can also purchase sand filter cleaner that you run through your pool’s filter system on an annual basis. This will clean microscopic oils and grease off your sand and help to increase its lifespan.

While cleaning and backwashing will help decrease water pressures and improve water clarity, you will still need to replace your sand at a certain point. If it’s been over 3 years since you’ve done it, it’s probably time.

How to change the sand in your pool filter

Materials you will require:

  • Filter sand in one of the three types listed above
  • Duct tape
  • Silicone
  • A screwdriver
  • A vacuum or bucket

Follow this step-by-step process to change your pool sand:

  • Turn off the power to your pool pump.
  • Remove the drain cap located on the bottom of your pool tank. Loosen it to remove the pressure and then fully drain the tank.
  • Unscrew the valve that connects the waste, pump, and return pipes.
  • Remove the collar or flange clamp that holds the filter in your tank. You’ll need a screwdriver to remove the screws holding it in place. Make sure not to lose the protective cover.
  • Take off the multiport valve.
  • Use duct tape to tape your pipe shut and avoid sand getting in. If you do get sand in the pipe, just be aware that you will find sand residue in your pool.
  • Take out the old sand. It’s easiest to vacuum out the sand with a shop vac, but you can scoop it into a bucket as well.
  • Rinse all remaining sand out of the tank with a garden hose.
  • Reattach the drain cap on your filter tank.
  • Fill your tank halfway with water.
  • Add the new sand to your filter. Consult the manual for your filter system to determine how much sand to add.
  • Replace your multiport valve.
  • Replace your standing pipe.
  • Reattach all the clamps.
  • Reconnect the pipes.
  • Backwash your pool for two minutes to clear debris out of the filter.
  • Rinse your filter for one minute.
  • Turn your pool pump back on.

Tip: Check your pressure gauge to make sure it is reading at normal pressure levels. If the gauge is reading higher than 10 PSI, you should backwash your filter again to regulate pressure.

Conclusion

Hopefully, this guide has helped you determine whether your pool needs a sand change and jog your memory on how to change it. If you’re having trouble keeping your pool water clean and have a sand filter system, it could be time to change your sand.

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