D.E. Pool Filters

D.E. Filter System

The D.E. (Diatomaceous Earth) filter system is known for having some of the best cleaning capabilities among the three main types of pool filters on the market.

Unlike a sand filter—where the filter function is controlled by a lever on top of the tank—a D.E. filter also has a handle on top, but it does not control the filter functions. To properly start a D.E. filter, follow these steps:

1. Ensure the pool water is at the proper level.

2. Bleed the air from the filter: Locate the bleeder valve on top of the filter head. Open the valve to release trapped air inside the tank. Once water begins to stream out steadily, close the valve.

3. Start the filter.

For branded systems like a Hayward D.E. filter, there is typically a chart that indicates how much Diatomaceous Earth powder to use. Generally:

• Smaller filters require about 3 one-pound scoops.

• Larger filters need 4 to 5 one-pound scoops.

You can purchase a D.E. scoop at a pool store, or use a one-pound coffee can as a substitute. While the filter is running, pour the D.E. powder into the pool skimmer. The system will pull the powder into the filter, where it coats the internal components.

Inside the tank are sponge-like structures called fingers. The D.E. powder coats these fingers, enhancing the filter’s ability to trap fine particles while allowing clean water to pass through. This is how a D.E. filter cleans your pool water.

Cleaning a D.E. Filter (e.g., Hayward System)

1. Turn off the pump.

2. Locate the drain plug or shutoff valve at the bottom of the filter. Most Hayward D.E. filters come with a shutoff valve, which should be installed to make draining easier. Water will begin flowing immediately once the plug is opened.

3. Attach a hose to the valve so you can direct the dirty water to a proper drainage area.

4. Open the valve and turn the pump back on.

5. While the pump is running, bump the handle on top of the filter several times. This breaks up and loosens the D.E. and debris from the fingers.

6. The water will initially be gray or green. Once it runs clear, the cleaning process is complete.

7. Turn off the pump and close the drain valve.

Note: If you want to reduce the amount of water flowing into your yard, you can open the drain valve without turning on the pump, allowing the tank to drain more slowly.

After Cleaning

You must re-add Diatomaceous Earth to the system just as you did during the initial setup. While the filter is running, pour the appropriate amount of D.E. powder into the skimmer to recoat the filter fingers.

Fall Closing

At the end of the season, a D.E. filter can be drained, cleaned, and stored indoors or in an outdoor shed—unlike sand filters, which must typically remain outside.

Disadvantages of D.E. Filter Systems

• Recurring cost: You must purchase D.E. powder and add it every time you clean the tank.

• Yard mess: The powder is discharged into your yard during cleaning. D.E. is bright white and can leave noticeable marks on your lawn, which some people dislike.

• Flow issues: As the filter ages, a common issue is a sudden drop in water flow. To fix this, you often need to turn off the pump and bump the handle (especially in Hayward systems), which can be inconvenient.

• Powder blowback: If there’s a loose screw or damaged fingers inside the filter, D.E. powder may blow back into the pool. This makes it look like dirt has settled on the pool floor.

• Repair cost: Replacing or fixing the filter fingers can be expensive. In many cases, people choose to replace the entire tank instead.