MGK Pool Service

DE Filter Cleaning – Advice Tips and Tricks

If you don’t know how to do a proper DE filter Cleaning, you might think DE is the worst. As a pool owner for 17 years, and having been servicing them for 30 as a business owner, trust me when I tell you, DE is the best way to go. But, if you don’t know how to take care of one, you might just want to blow up your pool and be rid of it. I have heard it a thousand times.

DE Filter Cleaning

It all starts with mis-information… “But the guy at the store said Bla Bla Bla”… The first thing I tell customers who do their own weekly maintenance, is this… The instructions for your filter are right on the side of it. That use to always be true, but now it is only sometimes true. I encourage anyone reading this post, to also read the instructions on their filter. You will literally be an expert having read both. Don’t you prefer to have an expert servicing your pool?

If you don’t have instructions on your DE filter, the model number and brand name are sure to be there. Google your model # + these keywords… Instructions + pdf. EXAMPLE: If you own a Hayward EC50, Type this into Google: “Hayward EC50 instructions + pdf” The very first article is this. It will not only tell you important information, like how much Diatomaceous Earth (DE) to put in it, it will give you insights into plumbing your filter correctly, and usually like a simple 8 step procedure to backwashing (aka cleaning your filter).

DE Filter Backwash

Backwashing is just a fancy way of saying get the old DE out of the filter. You can disassemble your filter and use a garden hose to clean off the DE, and rinse the filter housing. That is the most thorough way to clean a DE filter. But the beauty of most DE filters, is that you can get the old earth out without disassembling them.

Muli port Valve Backwashing

multi-port-valveIf you have a multi way valve, you just shut the pump off, turn the valve to backwash (usually 180 degrees from filter), and turn the pump back on. You run it in backwash mode until the water coming out the backwash line looks clear. Thats it… Now just reverse the procedure. Shutting the pump off, turn the valve back to filter, and turn the pump back on. Add the recommended amount of DE for your filter, and your good to go.

Remember to always shut the pump off be for turning the valve. Turn back on to operate. You might think that last part is common sense (turning the pump back on), you would be wrong.

Slide Valve Backwashing

Backwash Slide Valve
Backwash Slide Valve

Some filters only have a slide valve, those are simple too. Just shut the pump off, twist the T-handle to unlock, and pull it up. Turn the pump on and run until the water coming out is clear. To go back to filter, again just reverse the procedure.

No Valve DE Backwashing

Hayward DE EC Model Filter
Hayward DE EC Model Filter

Some filters dont have a valve to reverse the water flow. These are Hayward Perflex Filters. Models that begin with EC, as in the EC40, EC45, and EC50 for above ground pools. Or, EC60, EC65, or EC75a for inground pools. To backwash these filters, first you shut off the pump, then bump the handle, go down with the handle real slow, then jerk it up, do this eight times. Then either open the valve at the bottom of the filter tank, or take the plug out. I like to open the bleeder valve / air vent and let the filter gravity drain out before turning on the pump to flush it.

With Bump handle filters, I like to do this procedure twice before putting in new DE.

It doesn’t matter what brand you have, they all work the same. It will help if you try to wrap your head around how the filter works. Unfiltered water is delivered to the filter tank via the pool pump. In order for the water to get back to the pool, it has to pass through the grids, or flex tubes. So when you put DE into the filter, usually via the skimmer, it too tries to get back to the pool, but the grids prevent the DE from getting back to the pool, thus the grids get coated in DE. As the water passes through the DE coated grids, the water is filtered. Water is being forced from the outside in.

When you backwash the filter, as with the case if you have a valve, the pump water is directed to the inside of the grids, blowing the DE off the grids, and usually goes out to waste via a waste line. Water is being forced inside out.

DE filters are useless with out the DE powder. Worth repeating… DE filters are useless with out the DE powder in them. I should add that you need enough DE powder as well. Most filter take 5 lbs (read how much yours takes). That is equivilent to 5 1lb coffee cans. My favorite DE is called Celatom.

Filter Pressure Gauge

This gauge is used to tell how dirty your filter is. Water goes into the filter housing, and easily passes through clean DE, returning back to the pool. Once the DE is dirty, the water cant pass through it as easy, and the filter pressure rises. Once the filter pressure rises 7 lbs, it is time to backwash. Meaning it is time to get the old earth out and put the new earth in. Index the gauge after cleaning so you know when it goes up 7 lbs.

Think of it like a vacuum cleaner with a bag… What happens to the suction of your vacuum once the bag starts to fill up? It is awful… Think of the DE as a vacuum cleaner bag, once it starts to fill up, your filter is not working well. A filter that is not working well, means dirty pool water. but worse.

Another couple ways to know your filter needs backwashing. When your filter is clean, you have a good flow of water back to the pool. If you get use to how strong the stream of water look where the water is returning to the pool, and then you see the flow decrease, you my friend have a dirty filter.

Some people install a flow meter in their plumbing. This is a great way to check the efficiency of the filter. Water flow is effected long before filter tank pressure rises.

PRO TIP* Algae grows in areas of poor circulation. A pool with a dirty filter is much more prone to algae growth.

DE Filter Types

There are several brands, with Hayward and Pentair being the most popular. But you may not know, some of the guts are different, and your DE filter cleaning method is different too.

Hayward DE Flex Tube Assembly
Hayward DE Flex Tube Assembly

The old EC models were my favorite, and still are for some applications. The inside of this filter looks like fingers hanging down. The fingers are called flex tubes, and the tubes are just lengths of plastic tubing with holes, covered in socks.

I would recommend disassembling this filter for cleaning after having backwashed it twice. The DE jams up near the plates. For regular maintenance, hose off the DE, then spray it down with a product like Bioguard Kleen IT, let it soak for five minutes before rinsing one more time.

Every other year, you can fill a bucket with a 20:1 ratio of muriatic acid and soak until all bubbling stops. I personally would just replace the flex tube every three to five years with regular maintenance. But for that deep clean, or to get one more year, go with a muriatic acid dip.

Least Favorite DE Grid Filter Type

DE filter Grids
DE filter Grids

The most popular right now, and my least favorite DE filter has grids covered in a this weak mesh material. These I would disassemble after already having backwashed 3 times. These filters do not always backwash out all the earth either, so manual cleaning with a hose becomes necessary.

These are my least favorite because they are expensive, and the grid material is prone to ripping. These need to be thoroughly inspected every time they are disassembled for service. Look closely on the bottom of these grids for wear, and tear. You can expect to replace a couple grids every other year. Not fun 🙁

Any hole in the grids means DE will be getting back to the pool. If it looks like you have white powder or sand collecting on the bottom of your pool.  Chances are good that you have a tear somewhere.

It is best for non handy homeowners to just keep flipping the filter over and hosing in the gaps to get the DE out. But your more handy homeowners may prefer to pull the two nuts off, and completely disassemble the grids for cleaning and inspection.

Favorite DE Filter Type

There is a new style cartridge DE hybrid. The mesh is much more durable, and cleans a lot easier than all other models. They are mainly for inground pools, but I could make a case for using the smallest version on an above ground pool. It’s Pentairs Quad DE Cartridge Style. It comes in three sizes… The 60, the 80, and the 100 square foot model.

Like all other DE filters, I would disassemble and clean it every 4th maintenance cycle, rather than Backwashing again. But it cleans up so sweet. I actually took a video out in the field earlier this year.

Assembling and Disassembling

As you know now, you will need to take apart your filter and clean it every so often with a hose, and maybe some Bioguard Kleen It detergent. I just want to point out that there are always o-rings. These o-rings seal certain areas and keep water from passing by. Anytime you see an o-ring, inspect it for wear, and make sure it is lubed up. There are a bunch of products like Jacks Lube, or Haywards o-ring lube. But Vaseline works real well to.

If your worried about remembering where everything goes when putting it back together. Shoot a video as you take it apart. Or Google your brand and model number with this phrase “parts schematic”.


This pretty much sums up this article on DE filter cleaning. We have talked about cleaners, instructions, brands like Hayward and Pentair, grid types and my favorite type of DE. A couple more names you hear all the time is Earth or Diatomite. No matter what you call it, DE is just crushed up Diatoms.

Ohhh, a little more advice… Dont use your hands to brush off the grids while you are cleaning them. Those crushed up Diatoms are sharp, and will wear your skin off real easy. Also, when scooping up dry DE, or handling it when its in powder form, don’t breath it in.

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