D.E. Filters

D.E. (Diatomaceous Earth) Filters


Reasons why your D.E. Filter might be the cause of Green or Cloudy Water: (Note: For all the details about these reasons, see below.)


            1.) You have not been Backwashing every 2 Months or when the Pressure rises 7 lbs..


            2.)  You have not been Back Washing "PROPERLY". (Again, see below)


            3.) You have not been recharging your filter properly.        


            4.) Your Filter has not been COMPLETELY Pulled Apart and Cleaned at least once a Year.


            5.) Your Filter has Damaged Grids, Manifold or Other Internal Components.


            6.) Your Back Wash Valve is Damaged, Missing an O-Ring, has a Damaged Spider Gasket, ... (See Back Wash Valve Problems)

Diatomaceous Earth (D.E.) Filters (***NOTE: I DO NOT RECCOMEND "QUAD" D.E. FILTERS FOR HOME USE, EVER!!! See Bottom of page)

1.) If you are going to keep a decent eye on your pool equipment, and be consistent about it, OR, if you are going to have a 'qualified' Pool Professional handle your pool service, this is the filter you want. This is the filter I use. This is what I will be using on your pool if it is pea soup and you want me to turn it back to clear in 24 hours. However,


2.) If you are EVER going to consider 'Renting' your home, get a sand filter.

            a.) If, for any reason, while renting your home, the pool care quality slips, or someone fails to backwash when they should, AND FAILS TO DO SO EXACTLY as manufacturers tell you to do, you are going to have to replace the grids. 

            b.) Note: the same with cartridge filters, and the cost of a set of grids is about the same cost as a set of cartridges for a cartridge filter. The difference is, properly maintained, you will go through a set of cartridge elements every year to two years, even if you are taking care of your pool properly. With a D.E. filter, you 'SHOULD' only need to replace the grids every 5 years or so, again, IF you are taking care of it properly.

         If you are not going to take care of the D.E. Filter properly, or hire someone to take care of it properly, OR you are going to rent the property, DO NOT GET THIS FILTER! Otherwise, Get the D.E. filter. Properly maintained, it is the best, and will cost you the least to maintain.

3.) Because D.E. Filters Filter down to 4-6 Microns, they will pull almost all algae out of the pool (With proper water flow adjustments.), and even larger viruses. For clean, sparkling water, they cannot be beat.

4.) The only 'easier' filter to maintain is a sand filter, and that is because most home owners do not take the time to learn how to backwash D.E. Filters properly, and a D.E. filter needs to be pulled completely apart and cleaned approximately once a year. If you have “Mesquite” trees near your pool, open farmland just over your fence with a farmer who plows during wind storms, … then you will need to have your filter pulled apart completely, and cleaned completely at least 2 times per year.

5.) Because of their filtration, most pools using a 'Properly Maintained' D.E. filter, and 'properly maintained' water chemistry, require about 25% less operation time than Sand or Cartridge filters require. Also, because it is taking out a lot of the 'Fertilizer' and Algae Spores, that the other filters miss, I notice an average of about a 25% reduction in chemical costs over a similarly maintained Sand or Cartridge Filter installation.


1.) D.E. Filters work by pushing unfiltered water into a tank. The water is then pushed through a layer of fossilized plankton (Diatoms) that attaches itself to the cloth covering a plastic framework designed to allow the filtered water to pass through and reenter the pool through the pool returns (Or Floor Heads). D.E. is harmless, unless inhaled. AVOID SNORTING YOUR D.E.!!! It causes similar problems to Silicosis of the lungs. Other than that, it has even been used as an abrasive in toothpaste. (Eating, in small amounts, is ok... DO NOT INHALE!.)

2.) For most 'New' Filters, the recommended number of pounds of D.E. to add will be listed on the side of the filter. As a general rule of thumb, most manufacturers today recommend that you divide the total filtration area (Usually 24, 36, 48, ... square feet) by 10 and recharge the filter with that many pounds of D.E..

3.) When starting with a 'New' or 'Freshly Cleaned' filter, I will normally add 1 more pound than the manufacturer recommends. Once the D.E. has been added this first time, I will write down the filter's starting pressure. This is a guideline for when I will need to backwash again, and when the filter may need cleaning.

4.) As the D.E. filter operates, more and more dirt, debris, algae spores, ... get stuck to the layer of powder on the outside of the grids. As this happens, the pressure rises.

            a.) For this reason, I normally will only run a D.E. filter a maximum of 4 hours at a time, leave it off for 2 Hours, and run it for up to 4 more hours. Why, Each time a D.E. filter shuts off, most of the D.E. falls off the grids, and then, when the equipment comes back on, it presents a fresh surface to catch dirt, debris, algae, bacteria, and even some of the larger viruses. This process of “recharging” takes at least an hour, sometimes 2. In severe cases of cloudy or green water, I will run a D.E. filter 4 hours on, 2 hours off, 4 hours on, ... for an entire 24 hour period. (Yes that requires 4 sets of on/off trippers for your pool time clock.)

5.) Running a D.E. filter for longer than 8 hours will cause the dirt and debris that sticks to the filter to form a crust that will not permit the D.E. to fall off and recharge properly. REGARDLESS OF THE TIME THE EQUIPMENT IS LEFT OFF. Do not run your D.E. filter longer than 8 hours at a stretch, regardless of what anyone says. You will set everything up like concrete, and if you do not have your filter completely pulled apart and cleaned, you will destroy your grids. When you do this, the pressure continues to rise, and the cloth material is pushed against the plastic frame with more and more pressure. This causes catastrophic failure of the cloth material, the plastic grids to break and collapse, and Manifolds(the assembly the grids fit into) to crack and fail as well. This is why D.E. filters are not for those that are not going to keep a regular eye on their equipment, or for those letting the renters take care of pool care or hiring pool service.


1.) Every 2 Months, or whenever the pressure rises 7 lbs. from the pressure recorded in 'Operation' 'Step 3', whichever occurs first, I will backwash all D.E. Filters.

2.) Every year, or when the pressure AFTER BACKWASHING AND RECHARGING is STILL 7 lbs. Greater than the pressure I recorded in 'Operation' 'Step 3' above, I will completely pull apart, clean and inspect each D.E. filter. (Note: It's an hours labor, about a $125 . I suggest you pay to have it done, and watch closely before you try it yourself.) (Note: If you have more than ONE damaged Grid, replace them ALL. In 90% of the cases where (2) or more grids were damaged, I got a call back within 6 months (Usually one or two months) because another of the grids had failed. This is another hours labor, plus the cost of the grids. TRUST ME! You will pay DOUBLE, or possibly triple the cost of a complete set if you do not replace them all. If only one grid is bad, I will replace, or on rare occasions, repair, that one grid, but I always warn the customer that there may be a call back, and it is they who are shouldering the risk.


            a.) Turn Off Equipment. ( Note: Before EVER moving a backwash valve on ANY sand or D.E. Filter, make sure the equipment is off! Not doing so can cause damage to your equipment, not to mention damage to you! )

            b.) Put Backwash Valve into the backwash position.

            c.) Turn on equipment.

            d.) Run Till Backwash water is clear.

            e.) Shut Off Equipment

            f.) If you have a 'Dial' Backwash valve Turn it to Rinse. If you have a 'Push/Pull' Backwash Valve put the valve back in normal operation position.

            g.) Turn on your equipment for 20 seconds.

            h.) REPEAT STEPS a-g UNTIL THE WATER STAYS CLEAR AND NO MORE DIRT COMES OUT THE HOSE AT ALL! This is essential or you will not get all of the D.E. you can off the grids and your pressure will continue to increase and damage your grids, or require a premature filter clean.

            i.) Shut off Equipment.

            j.) Put the Backwash valve back in normal pool operation position.

            k.) Turn On Equipment

            l.) Add the proper amount of D.E. to Skimmer (Usually on the label)
A.) Remove float Valves ('Flying Saucer' shaped disks found below skimmer baskets in some pools.) before doing this step. Put them back when this step is completed.
B.) Note: Most 'New' filters have the number of pounds of D.E. to add on the label, or you can divide the Square Foot in the 'Filter Area' column by 10 to get an approximate number.
C.) Most often I do not 'Pre-Mix' my D.E.. I add it directly to the skimmer with the skimmer basket in place (Without the diverter/Float Valve.) being careful not to inhale any. (See the warning above.) trust me, this is easier than trying to mix it into a slurry and gives the same results.
        This process is not 'Hard'. Plus, unlike a sand filter, it doesn't get done every week, usually it is done every 8 weeks. that said, the labor to maintain is actually less than a sand filter, and way less than a Cartridge. Cost of D.E. is less than 40 cents a pound. That's less than $2.00 a recharge. Considering the operation time savings and the savings in chemicals, not to mention how the water sparkles, you can see why I like D.E. filters.

Note: You can either get a 1 lb. Coffee can, which is about the same size as an 'official' D.E. scoop so that you get the right amount added. This material goes by 'Weight' not by volume.


*** Quad D.E. Filters, or "Cartridge Filters" with D.E. material, are not recommended for the same reasons that cartridge filters are not recommended. They cannot be effectively backwashed effectively because of the pleated material, and so have to be pulled apart and manually cleaned every month or two. The only difference is that they have the filtration of a D.E. filter, which is slightly better than a cartridge filter, and, when cleaned and recharged, they retain their original flow rates, unlike cartridge filters where the flow rate gets progressively worse until the elements need replacing.