How to Clean and Backwash a DE Filter

There are many things to keep track of when cleaning and maintaining your swimming pool. Unfortunately, certain steps can be forgotten at times. It can come as a surprise when checking your DE (diatomaceous earth) filter and finding it is in a decrepit state. But not to worry, as although there are some crucial steps to follow, the cleaning process is pretty straightforward.

In this article, I will outline a detailed step-by-step guide on how to clean your DE filter and the supplies you will need on hand.

What is a DE Filter?

DE filters use diatomaceous earth to filter out the smallest particles from your pool water. Diatomaceous earth is a much finer material than sand, so it is able to block much smaller particles from reentering the pool water.

Because the particles are so small, you will need to clean the filter more often than a sand filter, and you will need to replace the DE in the filter.

Supplies Checklist

Here are some of the tools and supplies you will need to clean out your filter:

  • Bucket
  • Garden hose or backwash hose
  • Lubricant
  • Towel
  • Socket wrench (only for certain models)
  • Enough DE for your filter size

Step-by-Step: How to Clean a DE Filter

Cleaning out your DE filter may seem intimidating, but it is a straightforward process in reality. I recommend that you clean out your DE filter every 1-2 months. Doing so will maximize the lifespan of the filter and keep your pool nice and clean.

Step 1: Check the pressure gauge

Your pressure gauge will tell you when to clean your pool. When the pressure is 8-10 psi over the usual readings, it is likely time to clean the filter. The pressure gauge is located on the top of the machine and will read the internal pressure of the filter. Read my article on what to do when your DE filter pressure rises fast for more tips on common problems.

Step 2: Backwash

Turn your filter to backwash and start the pool pump. Continue backwashing until the wastewater is clear.

Step 3: Drain the water from the filter

After the backwash is completed, turn off your pump. Then open the air release valve and the drain plug, and drain out all of the water in the filter.

Step 4: Remove the clamps or bolts holding the filter cover

Once the water in the filter has drained, you need to take off the top of the filter. Some models will have bolts that need to be unscrewed with a wrench, while others have a single clamp that needs to be released.

Step 5: Remove the manifold

Remove the top of the filter and take out the manifold, which holds each of the filter grids. When it is dirty, you will see plenty of grime and debris on each of the filter grids.

Step 6: Wash each filter grid

Each filter grid should be removed from the manifold and washed using a garden hose. Make sure to get in there and clean off all the DE, debris, and algae from the filter grids.

Step 7: Rinse the filter tank

After cleaning the filter grids, you should also give the filter take a good rinse, removing any excess DE from the walls of the tank.

Step 8: Put the manifold back in the filter base

Place each filter grid back in the manifold and return it to the filter base. Lubricate the O-ring in the tank and put the filter lid back on. Secure it with either the clamp or bolts.

Step 9: Prime the pool pump

Fill your strainer basket with water, allowing some water to run through the pump. It is best to fill the pump with some water before turning everything back on. Read my entire guide on how to prime a pool pump for more on this step.

Step 10: Release all air in the tank

Open the air release valve, removing any excess air.

Step 11: Turn the pump on

Once all of the air in the pump is released, turn the pump back on and close the air release valve when you see the water coming out.

Step 12: Calculate the amount of DE you will need to add

Now that the pump is running, calculate how much DE your filter needs. DE filters are generally between 24 and 60 square feet. You can usually find the square footage of your DE filter on a label located on the side of the machine. Then, all you need to do is divide that number by 5. This calculation will give you the number of scoops of DE to add to your filter.

For example, let’s say you have a 36 square foot DE filter. 36 / 5 = 7.2. Therefore, you should add 7 scoops of DE.

Step 13: Put the necessary amount of DE in a bucket and mix

Add the DE scoops to a bucket and mix with water. Mix the solution generously so that the DE does not settle at the bottom of the bucket.

Step 14: Pour the mixture directly into the skimmer

Pour the mixture into the skimmer, and add more water to the bucket if excess DE is stuck to the sides.

Step 15: Allow your pump to run for about 1 hour

Keep the pump running for 30 minutes to 1 hour, allowing all of the DE to make its way to the filter and collect on the sides of the filter grids.

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Frequently Asked Questions

How Often Should You Clean Your DE Filter?

At the very least, I would recommend cleaning your filter once per season. However, depending on the amount of use the pool gets and how well you maintain it, it may require cleaning more often. Check your filter’s pressure gauge monthly to make sure it is at the correct psi, and clean it out if needed.

What Are the Signs That You Need to Clean Your DE Filter?

The main thing to keep an eye out for is the pressure gauge. When the reading is 8 psi or more over the standard reading, you should consider cleaning the filter. However, the pressure gauge isn’t the only sign that your filter needs maintenance.

If your pool is cloudy or if you notice DE has made its way into your pool, you should open up the filter and take a look. This could not only be a sign that the filter needs cleaning, but also a sign that the filter grids may need replacing.

Do You Have to Add DE Powder Every Time You Backwash?

Every time you fully clean and backwash the DE filter, you will need to completely restock the DE. Sometimes, you won’t need to completely clean the filter but only backwash it. In this case, you only need to restock around 75 percent of the DE powder as the filter grids will retain some of the DE.

Bottom Line

Your DE filter is one of the best tools you have for combatting nasty debris, algae, and contaminants in your pool. It works hard for you, so make sure that you take care of it and clean it out when necessary. These filters can last a very long time if maintained and will keep your pool clean and sparkling for many seasons to come!

If you find that you need more extensive work on your DE filter, check out my guides on common DE pool filter problems and how to replace your DE filter grids.

And if you need a brand new filter, check out my list of the best pool filters. I also have several other cleaning guides, which you can find on my main page for how to clean a pool filter and how to backwash a pool filter.

Do you have any further questions? Feel free to reach out as I’m happy to help.

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