Plumbing, Heating and Pool Repair Guides

How To Troubleshoot D.E. Pool Filters


The Diatomous Earth swimming pool filter, commonly known as the “D.E. Pool Filter” for short can be a great asset to your pool water during the summer. However when your D.E. pool filter starts to give you trouble or causes problems you will have to preform something called “Pool Filter Troubleshooting”. When you troubleshoot your D.E. pool filter you will be eliminating what parts are good and won’t need to be replaced. You will also be able to find out what parts have failed on the D.E. pool filter and then be able to replace them.How To Troubleshoot D.E. Pool Filters

Even though there are many different models and styles of Diatomous Earth swimming pool filters, the internal / external parts like filter grids, filter grid manifolds, o-rings and multiports work in the same way. These parts are also the ones that commonly fail or will need to be repaired no matter what brand or model filter you have. Most problems that you will experience with a D.E. pool filter will be caused by lack of proper maintenance by the owner. This includes leaving the pool filter out in the winter elements in the off season, not acid washing the pool filter grids, not replacing needed parts like failing mulitports and leaking o-rings. All of these parts will start to show age and wear before they fail but often they are not replaced until they completely fail. There will of course be unique situations where your D.E. pool filter is experiencing something that no one has ever seen before but there are also many common problems with D.E pool filters.

There are also two different types of D.E pool filters. Some D.E filters will use grid to filter the pool water and others will use something called “fingers”. These finger filter grids are found mostly in the Hayward EC-series pool filter line. Filter Grids and Filter Fingers can give you the same kind of problems as they are both covered in a fine mesh. If this mesh becomes damaged on either a D.E. filter finger or on a grid the D.E. powder will wind up back in the pool. So just because one is shaped like a finger and one is shaped like a grid, that doesn’t mean any one is stronger or won’t give you less problems, as they both will if damaged.

Problem: “My Pool Filter Is Putting D.E. Back Into The Pool”

Solution: When a D.E. swimming pool filter lets d.e powder back into the swimming pool it means that the filter grids, filter fingers, filter manifold or the multiport is bad. When the filter grids have a rip or tear in them they will allow D.E. to pass back into the pool. When the manifold is cracked it will do the same. If the multiport is bad it can cause the D.E. powder to not go into the filter at all and instead go directly back into the pool. If you are seeing small amounts of D.E. powder in your pool chances are that you have a rip or tear in your filter grid.

Problem: “My Hayward EC-series D.E. Pool Filter Is Allowing D.E. Powder Back Into The Swimming Pool and I have found no rips or tears in the fingers”.

Solution: The Hayward EC series line of filters not only uses filter fingers but also uses something called “tube sheets”. These tube sheets are the plastic disks that all of the fingers slide through. There is a top and a bottom tube sheet in all Hayward EC series pool filters. Chances are that you have cracks in your tube sheets. Look in the center of the tube sheet and you will see spider cracks in the tube sheet. These types of cracks are caused by bumping the handle to hard when back washing. Replace the cracked tube sheets and D.E. powder will not go into your swimming pool any longer.

Problem: “My multiport is on filter but the pool is not clearing up”.

Solution: Just because the multiport dial is set on the filter mode does not mean its actually working correctly. Many times the spider gasket inside of the muliport will go bad and then you will think the pool is set on filter mode but the water is really being diverted to the pool or out the backwash line instead. Replace the multiport or the mulitport gasket to correct this problem.

Problem: “My D.E. Pool Filter Gauge Shows High Pressure Even When Its Not Running”

Solution: If the gauge on your D.E. pool filter shows a high pressure even when its off then most likely your gauge is broken and needs to be replaced.

Problem: “Where Can I have My Pool Filter Acid Washed?”

Solution: Most swimming pool supply centers will offer swimming pool filter acid washing. You will usually have to bring down your pool filter grids or fingers and they can acid wash them for you. You can also soak your grids in white vinegar to help cleanse your filter grids as well.

Problem: “How Do I access My Filter Grids Or Fingers?”

Solution: You will need to remove the bolts around the flange or remove the belly bad nut and spring. Once you do either one you will be able to access the filter grids.

Problem: “My Backwash Line Has Water Coming From It When On Filter.”

Solution: If your backwash line has water coming from it when the swimming pool pump is running and the mulitport is set on filter then this means that you have a bad multiport gasket or possibly the entire multiport is bad. You should change either the gasket or the multiport.

Problem: “How Do I bleed The Air From My D.E. Pool Filter?”

Solution: You can bleed the air out or your D.E. pool filter by using the air bleed screw that will be on top of the filter. Most new filters will have an auto air bleed that will bleed the air for you. If you are looking to bleed the air out of the Hayward EC style filters then you will find the air bleeder screw right by the discharge fitting. On other D.E. pool filters the air bleed screw is usually near the gauge on the pool filter. The air bleed screw is also always on the highest point of the filter.


  1. I opened my pool this week and while it seems to be filtering ok, I don’t have really good suction through my skimmer…the basket wants to lift up a little and not set flat on the bottom….

  2. Im having problems with my filter. I have acid washed and backwater my filter. When starting filter pressure runs12-14 and has good water flow and suction. After about 15 min. pressure is up to 20-22 psi water flow is terrible. any ideas of possible issue remedy?

  3. Keith
    I replaced my D E filter and I’m having the same issue. Great water pressure at first, then after about 30 minutes greatly reduced water flow.

  4. Question, my filter grids are only holding DE on top halves of them all. Front & back, covered in DE, but only half way up. I’ve taken them all out, backwashed tank, etc & get same results. Help!

  5. how long should I soak my filter fingers in a bucket with 1 gallon of acid wash and 4 gallons of water?

  6. Pentair FNS plus DE pool filter. Replaced the Multiport valve and filter top manifold. Fins are filling with water and DE. DE should be on the outside of the fins. What could be wrong. The water is still entering the pool through the jets and leaving through the skimmer and drain. Fins are like big pillows when I open the filter housing.

Leave a Comment

Your email address will not be published.

This div height required for enabling the sticky sidebar
Ad Clicks : Ad Views : Ad Clicks : Ad Views : Ad Clicks : Ad Views : Ad Clicks : Ad Views : Ad Clicks : Ad Views : Ad Clicks : Ad Views :