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How To Operate & Clean A Pool Sand Filter Properly: Step-By-Step Instructions

how to operate a pool sand filter

Sand filters are used to remove fine particles from water. Sand filters are usually placed near the return pump of the swimming pool. They are designed to remove dirt and debris from the water.

A sand filter consists of a tank filled with sand.

Water enters the top of the tank and flows down into the bottom, where it passes through the sand.

The sand acts as a filter as the water travels through the sand.

Types of Sand Filters

how to operate a pool sand filter

There are two types of sand filters: mechanical and chemical.

Mechanical Sand Filters

Mechanical filters are typically used in smaller pools, such as spas, kiddie pools, and above-ground pools. These filters are often self-contained units that sit on the pool floor.

They consist of a motor, impeller, and filter cartridge. The motor turns the impeller, which pushes the water through the filter cartridge.

Mechanical filters are made of metal mesh. These filters are very effective at removing small particles.

The filter cartridge contains a layer of sand or gravel that removes particles from the water. The water then passes back into the pool.

Chemical Sand Filters

Chemical filters are designed for larger pools, such as above-ground pools, inground pools, and commercial pools. They are also used in spa systems.

These filters contain a tank filled with chemicals that kill bacteria and algae. A pump circulates the water through the filter bed. As the water passes through the filter bed, it picks up the chemicals.

The chemicals react with the bacteria and algae, killing them. Then the water passes back into the pool or spa.

Filters should be cleaned regularly to ensure they continue working properly. Cleaning a filter involves removing the cover, opening the valve, and draining the water out of the filter.

Then the filter is rinsed with fresh water. Finally, the filter is refilled with water and closed.

What Are Sand Filters, And How Do They Work?

how to operate a pool sand filter

Hollow tanks are used for sand filtration systems – just like with other pool filter types.

The central pipe inside the tank is usually made from PVC plastic. Old sand filters usually have a metal pipe, though they’re not common.

The pipe extends from a diffuser at the top of the water filter tank down to the tank’s base, where it enters a manifold or hub.

There’s a series of slots at the base of the tank where water flows into the tank through them.

An adjustable valve attached to the top of the container lets you control the flow of water through the container.

Sand is at the heart of the operation, of course.

Sand filters cleanse the water by trapping particles within the compacted sand structure that is usually placed inside the tank and around its internal plumbing. Typically, the tank is about halfway filled with sand, so you need to know how big your tank is before buying the sand. 

When the pump is turned on and the valve is set to “filter,” it forces pressurized water through the tank. Water is pumped from the river into the reservoir.

From there, it flows through the filter, cleans the water, and enters the manifold pipe. Water then collects in and rises up through the center pipe. At last, the clean water flows from the valve into the pool.

Backwashing reverses the flow of water, moving the dirt from the filter and through an outlet pipe or hose before it gets dumped outside.  This mode is used to clean the sand filter (see steps below).

How to Clean A Sand Filter: The Basics

Cleaning a sand filter is easy and consists of three basic steps as follows:

What is Backwashing?

Backwashing is cleaning out the inside of your filter cartridge by running clean water through it.

This procedure helps keep your pool cleaner longer by preventing algae growth.

How to Clean A Sand Filter: Step-by-Step Instructions

how to operate a pool sand filter

Step 1: Start The Filter System

Turn on the power switch on the sand filter unit. Turn off the water supply valve before starting the sand filter.

Step 2: Drain The Water Out Of The Sand Filter

Open the sand filter cover and drain the water into the sand filter waste pail.

Step 3: Fill Up With Fresh Water

Put the sand filter back in its place. Then, refill the sand filter with water from the main tank.

Step 4: Run The Sand Filter For Several Minutes

Run the sand filter for about 5-10 minutes.

Step 5: Stop Running The Sand Filter

Turn off the power switch. Open the sand filter cover.

Step 6: Check If The Sand Filter Is Ready

The sand filter is ready if you see no dirt or debris in the sand filter waste pails.

Step 7: Empty The Sand Filter Waste Pile

Empty the sand filter waste piles into your sand filter waste container.

Step 8: Reinstall The Sand Filter

Put the sand filter into its place. Tighten the sand filter screws so they are adequately sealed.

Step 9: Test The Sand Filter

Turn the filter on and let it run for several minutes before turning off the power. 

Step 10: Maintain The Sand Filter Regularly

Clean the sand filter every month. Remove any leaves or debris that accumulate inside the sand filter.

A Few Important Backwashing Tips

how to operate a pool sand filter

Backwashing is essential to maintaining a healthy sand filter.

However, there are some things you should know about how to do it properly.

Here are a few tips to help you avoid problems with sand filters.

1. Know Your Filter Type

There are three kinds of sand filters: gravity flow, pressure drop, and vacuum. Gravity flow filters are usually used in smaller applications where space is limited. Pressure drop filters are typically found in larger installations. Vacuum filters are generally used in large applications.

2. Be Careful About Water Quality

You want to make sure you’re not wasting any water during backwashing. If the water from the sight glass looks clear, yellowish, cloudy, dirty, or contains sediment, you probably don’t need to backwash.

3. Keep It Clean

If you notice any buildup of dirt or debris in the filter, you’ll need to backwash sooner rather than later. Remember, the water coming out of your sight glass should look clean. If it doesn’t, you might need to backwash. You probably don’t want to backwash if you see sediment in the water.

Reduce the Need to Backwash

Leaves and other debris can lead you to backwash your pool pump more frequently or even dump the whole thing out if the water becomes too dirty.

But one of the best ways to keep this from happening is to install a quality pool cover.

A good pool cover reduces the number of dirt particles entering the system and keeps the filter clean. This allows you to backwash less often and save money over time.

Do you want to learn more about how to choose the right pool cover to reduce the need to do backwashes? Then check out our comprehensive guide to choosing the right pool cover.

Make Backwashing Easier

Backwashing is often a chore for many people because the process requires getting down into the filtration system and working your way around each element.

But there are ways to make backwashing easier.

For example, if you use a multi-port valve, simply disconnecting the valve allows water to flow freely through the system without clogging up the ports. This makes backwashing much simpler and saves you the trouble of going down into the system to clean the filters.

Tips for Maintaining a Sand Filter

how to operate a pool sand filter

Regularly cleaning the filter helps ensure that the filter remains efficient.

  • Use a hose to wash away any debris that accumulates inside the filter.
  • Clean the filter regularly.
  • Avoid using harsh chemicals to clean the filter.
  • Cleaning the filter too often can damage the filter.
  • Make sure that the filter is always full of sand.
  • Do not place the filter directly over the drain.
  • Never put the filter under pressure.
  • Never allow the filter to run dry.
  • Always follow the manufacturer’s directions for maintenance.


Q: What is a sand filter?

A: A sand filter removes solid particles from the water in a swimming pool. These particles include dirt, rust, and other debris.

Q: How Much Does a Sand Filter Cost?

A: A typical complete sand filter system requires a pump, filter media, a screen basket, a motor, and a control panel. Depending on how much power you want to put into your filtration system, you could spend anywhere from $1,500 to over $10,000 to add a sand filter system to a pool.

Q: What Does Sand Filter Sand Cost?

Replacement sand for your sand filter usually runs around $25 per 50 pound bag, and your filter might require 100 to 600 pounds of sand, depending on the size and type. For an average-sized inground pool filter, you’ll need about 350 pounds of material.

However, the main expense when buying and installing a sand filter is purchasing and setting up the equipment.

Q: How much space do sand filters take up?

A: Sand filters usually don’t take up very much room. However, they do require some space around them.

Q: Is a sand filter safe?

A: Yes. Sand filters are made out of solid materials that prevent leaks.

Q: How long should a sand filter last?

A: The life span of a sand filter depends on how often you maintain it. Most manufacturers recommend replacing the filter every two years.

Q: Are sand filters easy to operate?

A: Yes! You must refill the sand with new sand each time you change the filter, but that’s about it.


Sand filters are essential parts of swimming pools. They keep the water clear and free of harmful bacteria and algae.

Sand filters are relatively inexpensive to purchase and install. Regular maintenance keeps them working efficiently.

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