Diatomaceous Earth for Pool Filters: How Do They Work?

If you want sparkling pool water without a ton of extra effort, your filter has to pull its weight. Most pools use one of three types of filters: sand, cartridge or DE (Diatomaceous Earth).

So, what is a DE filter, and why do so many pool owners swear by them? Well, a diatomaceous earth pool filter can catch the tiniest particles, giving you ultra-clear water that other systems just can’t compete with. It does this with a fine powder made from fossilized algae. This traps dirt and debris before it ever makes it back into your pool.

In this post, we’ll break down how DE filters work, how to maintain them and what to do when something goes wrong.

How DE Filter Systems Work

Let’s talk about what makes a DE filter so good at keeping your pool water crystal clear. DE stands for diatomaceous earth, which sounds kind of intense. However, it’s really just a super fine powder made from fossilized algae. When you add it to your filter, it coats a grid inside and creates a super thin layer that traps all the tiny stuff floating around in your water.

And we mean tiny. A DE pool filter can catch particles as small as 1 to 3 microns. That is smaller than what sand or cartridge filters can grab. That’s why a lot of pool owners swear by them, especially if they want that extra-clear, polished look in their pool water.

You’ll just want to keep an eye on the pressure gauge. If it creeps up 8 to 10 PSI above the normal “clean” level, it’s time to backwash the filter. That just means you're clearing out all the gunk it’s collected so it can get back to doing its job. 

How to Backwash a DE Filter System

Backwashing might sound strange, but it’s really just a simple way to clean your DE filter. You do it by flipping the water flow backward. This process flushes out all the dirt and debris that’s built up on the filter’s grids. So, it can keep working efficiently, and your pool stays clean.

Depending on your pool’s setup, you’ll do this using either a side valve or a multiport valve. Both will get the job done, but they work a little differently. Don’t worry, we’ll walk you through each method step-by-step so it’s easy to follow.

Backwashing with a Side Valve

Backwashing your DE filter might sound tricky, but it’s actually pretty straightforward. Just follow these steps to get it done right.

1. Turn Off the Filter: First things first, switch off your filter. If you have a backwash hose, go ahead and hook that up now.

2. Lift the Plunger: Next, pull the plunger up about three inches to unlock it.

3. Open the Air Bleeder and Start the Pump: With the plunger up, open the air bleeder valve and turn your pump back on. Let it run until the water flowing out of the hose runs clear. This usually takes about two minutes.

4. Rinse and Repeat: Turn off the pump, push the plunger back down and then repeat the backwashing steps three times in total.

5. Add Fresh DE Powder: After your last rinse, turn the pump on at low pressure and add the diatomaceous earth powder. Keep an eye on the pressure gauge as you do this to make sure everything’s running smoothly.

That’s all there is to it! Regular backwashing will keep your DE filter working its best and your pool water sparkling clean.

Backwashing with a Multiport Valve

If your pool has a multiport valve, backwashing your DE filter is still simple, you just need to follow a slightly different set of steps. Here’s how to do it right:

1. Turn Off the Filter and Switch to Backwash: Start by turning off the filter. Then, flip the valve from “filter” to “backwash.”

2. Attach the Backwash Hose: If you have a backwash hose, connect it now. If not, just open the waste valves so water can drain out.

3. Open the Air Bleeder and Start the Pump: Once water starts flowing through the hose, turn the pump on and let it run until the water runs clear. This usually takes about three minutes.

4. Rinse the Filter: Turn the pump off, switch the valve to “rinse,” and run the pump for about 10 seconds to settle everything back in place.

5. Repeat the Backwash: Switch the valve back to “backwash” and repeat the process three times total.

6. Add Fresh DE Powder: When you’re done, turn the valve back to “filter,” add the diatomaceous earth powder and turn the system back on. Keep an eye on the pressure gauge to make sure everything’s working smoothly.

Doing this regularly helps your filter stay in top shape. So, your pool water stays fresh and clear all season.

Troubleshooting DE Filter Systems

Even the best DE filters need a little TLC now and then. So, regularly checking your system helps keep everything running smoothly and your pool water clear.

If your filter gets clogged, the first step is to turn off the system and take out the filter grid. Give it a good rinse, and if needed you can soak it in cleaning solution. This gets rid of stubborn buildup.

Sometimes, your pool water might still look cloudy even when the filter seems clean. That could mean your filter just isn’t running long enough. How long you need to run it depends on your filter’s size and age; older filters usually need more time, while newer ones can often do the job faster.

Keeping an eye on these things will help your DE filter keep your pool sparkling all season long.

Taking care of your DE pool filter doesn’t have to be complicated. With a little regular maintenance and knowing when to backwash or clean, you’ll enjoy sparkling, clear water all season long. If you’re ready to upgrade your pool gear or need replacement parts to keep everything running smoothly, Vita Pool Supplies has you covered.

From pumps to filters and everything in between, they offer reliable, top-quality products that make pool care easier. Check out their selection today and give your pool the care it deserves!