How To Prevent DE Filter Powder Returning to Pool


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A common complaint with DE FiIter users is having DE Powder escape the filter and end up in the pool. There are a number of possible causes for this problem, some simple and some more involved. This guide discusses these causes and how to correct them.

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Step by Step


Step 1

AVOID ADDING TOO MUCH DE POWDER - One of the most common causes for getting DE Powder in your pool is adding too much DE powder.  Check your owner's manual for the manufacturer's recommended amount of DE Powder.  If this is a new installation, you will have to add the full recommended amount. But if you are replacing DE Powder after a backwash, you will not need to add the full amount - generally around 80%.  The grids will have retained some of the DE Power after the backwash, and if you add too much, it may end up in the pool. Use the DE scoop that is generally provided with the DE Powder to measure the amount of DE Powder to add. A 1 lb coffee can is not equal to a 1 lb DE scoop. Another guide to assess how much DE Power to add is to monitor the pressure gauge. Stop adding DE Powder when the gauge hits your normal operational range - generally 10-13 psi.

Step 2

CHECK MULTIPORT VALVE GASKET - If your Multiport Valve (MPV) Spider Gasket is damaged, you could have DE Powder leaking into the FILTER path during BACKWASH. A common cause of a damaged MPV gasket is the pool owner's failure to turn off the pump before moving the MPV handle. See our guide on "How to Replace a Spider Gasket on a Multiport Valve" for more information.

Step 3

CHECK FOR TORN GRIDS - Another common source of loose DE Powder is through a tear in the grid fabric. Remove and inspect each grid for signs of tears or a breakdown of the plastic core that has poked a hole in the fiber. Replace the grid with a new one if required. See our guide on "How To Remove and Clean Hayward DE Filter Grids" to see how to access these grids.

Click Here to Find Your Replacement DE Grid Pack 

Step 4

CHECK FOR DAMAGED MANIFOLD - While you have the DE Filter apart to look at the grids, check the Top Manifold for cracks around the ports and the Manifold Pipe Connection. Replace the Top Manifold if damaged.

Step 5

CHECK MANIFOLD PIPE FOR DAMAGE - Also check the Manifold Pipe that comes up from the side of the tank and connects to the Top Manifold. Look for cracks or breaks. Replace if damaged. Check the O-ring at the top of the pipe for cracks and wear.

Step 6

CHECK FOR SUCTION LEAKS - Another possible cause is backflow from the filter back though the pump and skimmer or suction ports. If there is a leak in the suction side of the piping, air can be sucked up the system and build up pressure inside the pool system while the pump is on. When the pump is shut off, this built up pressure can be released backwards into suction ports of the pool carrying some DE Powder with it. See our guide on "How to Identify and Correct Air Leaks" to check and resolve this issue.


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 Posted: 9/13/2021 

I just replaced my de grids this year with new ones from Pentair. Now I'm closing my pool. When I opened my Pentair de filter housing, all the de was at the bottom of the grids, on the inside, and the material on the grids themselves is very loose. No de on the outside of the grids at all, or on the manifold as in previous years. Any suggestions as to why the grids were not covered with de? No de went back into the pool that I could notice.

InyoPools Product Specialist  Posted: 9/13/2021 

The DE doesn't coat the grids like a batter. Instead, the DE will rise with the water level as it fills the tank. The force of the water passing through the grid coats them, making a screen of DE the water passes through to exit the filter.

 Posted: 7/9/2021 

I had a strange situation occur today. About 1 week ago I cleaned my DE filter completely and reloaded it with DE media. Everything ran fine for the past week. Today we got a lot of rain and I went to go drain my pool using the WASTE setting on my multiport - once I started draining DE media was pouring out of all the return jets into the pool and spa. At the same time I was still getting water coming out of the waste drain line. I have never seen this occur in the 5+ years I have been taking care of the pool. Any ideas what could cause this? Do you think the multiport valve could have a leak which is leading to this condition?

InyoPools Product Specialist  Posted: 8/4/2021 

There is either an issue with your multiport valve's spider/diverter gasket or the spring that stabilizes the diverter is loose. Further reading - Maintain and Repair Your Swimming Pool's Multiport Valve.

 Posted: 4/8/2021 

This is general information. I replaced my 30 year old Anthony filter With a pentair fns 48. I installed the new filter and charged it with 5 lbs DE. which by there instructions is 10 1 lb coffee cans of de. While charging I checked my pool and it was cloudy and after hour of running it was worse. My pool was full of DE Thought it was backwash valve rebuilt it and pool would not clean Long story a little shorter I took apart my brand new filter and the filter had come off the manifold pipe during shipping and also had one wing nut missing . So I just want to let you know with Pentair This can be a problem. If you buy one Take it apart first and save your self a ton of work

InyoPools Product Specialist  Posted: 4/8/2021 

Thank you for sharing, Dale! This will be useful to lot of people.

Anonymous  Posted: 5/24/2019 

Could a small hole in the grids, the size of a pen tip cause this problem?

InyoPools Product Specialist  Posted: 5/24/2019 

A pen, yes; but a pin, no.

 Posted: 4/17/2018 

Hello Tim - What is the make and model of your filter? What items have you replaced on the filter?

 Posted: 4/13/2018 

I am getting DE back into my pool. This only occurs when my filter first turns on every day. The DE comes out of the jet on the discharge side. It does not come out of the suction or skimmer side. I can see the DE shooting out of the jet for about 30 seconds and then it stops. What could be the problem? I have replaced many of the common parts that could cause a DE leak already.

 Posted: 9/19/2021 

Any answers to this question? I am in the exact same position and it is very frustrating. Tried many things but cannot find the problem. Help!

 Posted: 4/6/2022 

same problem here!. I replaced my manifold. my old one broke as I was moving it out of the housing so I replaced it and I noticed lots of cracks on the old one. funny thing is even before I broke it and it had all these cracks I never had all this DE spit back out on startup

InyoPools Product Specialist  Posted: 4/14/2022 

I'd check the standpipe o-ring on the filter housing pipe that hooks into the manifold port. If the original gasket from the old manifold was used with the new manifold, it could be causing sealing issues. Gaskets get stretched or warped pretty easily as they get older. The DE could pass the gasket as the water rises in the tank before it attaches to the grids. Or, if the issue only pops up after backwashing, you may not be rinsing for long enough.

 Posted: 3/9/2018 

ROLF - If your DE filter is only a year old, the grids should be sound unless, as you indicate, the pump is too strong for your filter. The GPM rating on the filter should be somewhat higher that the GPM rating on your motor. If the pump is trying to push more water through the filter than the filter is designed for, the filter will break down. One other consideration, clean out your filter, and only add 80% of the originally specified DE. Generally about 20% of DE is left in the filter after cleaning. If you add 100%, some of the excess DE will push though to the pool.

 Posted: 3/6/2018 

My DE Filter is one year old and I use a push pull valve. now I face the following problem. After starting the pump for ca.3 to 5 sec. the stream into the pool is dirty (de powder and dirt) after that the stream is pure. However a cloud of dirt is in the pool and has to filtered out until the next stop. And the it comes again. The filter meshes are tight, and all O rings not more than one year old. Can a to strong pump be one of the reasons??? Thanks in advance for a hint. Regards Rolf

InyoPools Product Specialist  Posted: 9/7/2017 

Karin - Replacing the grids into the bottom of the Grid Assembly can be confusing. We suggest taking the grids out, cleaning it and replacing it one grid at a time. See our guide on "How To Remove and Clean Hayward DE Filter Grids".

 Posted: 9/5/2017 

Informative. Is there an easy way to get the grid panels in after cleaning?

Anonymous  Posted: 5/25/2017 

very informative.