How Much D.E. Do You Put In That Filter?

In Tech Talk by Steve Donohoe3 Comments

Inside the D.E. filter: D.E. grid assembly from a 60 sq. ft. filter.

In our CPO class, when we talk about D.E. filters, we stress that it’s the Diatomaceous Earth (D.E.), NOT the grids, which is the filter media.  We have a D.E. grid as a classroom prop — and we show the students that it is designed only to hold wet D.E.  It’s an unusual concept to grasp at first, but the D.E. IS the filter media — NOT the grids.  And D.E. filter grids without D.E. are ruined D.E. grids!

So the question is:  how much D.E. should you put in a D.E. filter?  Well — the rule to follow is:  add 1 pound of D.E. for every 10 sq.ft. of filter area.  We, at Another Perfect Pool, have always used this rule — and added a little more.  The CPO Handbook on page 147 states: “Follow the directions as provided by the filter manufacturer concerning the proper amount of D. E. to use.  The normal amounts range from 1 to 1.5 pounds for every 10 square feet of filter area.  The commonly-accepted value is 1.25 lbs/10 ft2″. This equates to 2 ounces per 1 square foot of filter area.

It is very important to put in the correct amount of D.E:  too little D.E. will result in dirt, oils and other debris being embedded into the grids, ruining them.  Too much D.E. will result in the D.E. “bridging” between grids — reducing the filter area.  This will make the filter less efficient, raise the back pressure,  ruin the grids and make the whole circulation system underperform.

Steve and Kyle Maddox

The day before our Riverside CPO class, we attended the IPSSA Region 6 Table Top industry trade show in Redlands.  We had the opportunity to meet local industry manufacturers, suppliers and distributors there.  We also met up with a few of our former CPO students!  And of course we met with the PoolCorp folk — most of whom were from the Riverside SCP store.   Kyle Maddox was at the Table Top, too.  He is the Operations Manager at Riverside SCP and is pictured here with Steve.  We spoke about the CPO class to be held the following day — and indicated that we need a few additional tables.  “I’ll take care of it!”  Kyle said.  And so it was.  By the time we arrived Thursday morning at 6:45 — the tables were already carried upstairs, set up and ready.  — Thank you, Kyle!  And thanks, again, to all of the folks at SCP Riverside for your help and welcome hospitality!


  1. Thanks very much for the DE ratio information, which is what the mfg of my filter recommends. The pool guy who opened my pool this year said to use 2 cans (about 1# or less each), which about 1/4 the recommended amount! I have had a terrible time trying to figure out the pool; when I put in the recommended amount, the filter immediately began running much better.

    1. Same here! One pool store said 1# for 36 square foot of grid! Had “gunky”, “slimy” DE all the time, and high back pressure.
      Put in 3# (plus a little extra) and works great now! Wish I had dug a little deeper instead of taking the pool store’s word…lesson learned! 🙂

  2. I have a Hayward EC65A DE filter which has 27 sq ft of filter surface. The manufacturer calls for 6 lbs of DE media. Well I tried getting 6 lbs in there several different ways, slurry, slow powder pour etc. No matter what the whole filter got gunked up, bridging all the filter fingers and giving me super high pump pressure. From your formula this filter should maybe take 4 lbs max. I tried this formula and got a good even coat on the filter fingers with no gunking or bridging and good pump pressure. Thanks so much for this information.

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