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National D.E. Day!

Published by Brooke Sardella on Aug 31 2022

National D.E. Day!

Today is National DE Day! Here at E-Z Test, it is like this day was created just for us! DE stands for Diatomaceous Earth. It is a crumbly sedimentary rock formed by billions of fossilized microalgae organisms called diatoms. Diatoms alive today are responsible for creating 75% of the earths oxygen - they deserve to be celebrated!

When diatoms die, they fall to the bottom of bodies of water and solidify. They are then mined in a variety places such as rivers, steams, lakes and oceans around the world. Diatoms are mainly composed of silica, one of the most abundant substances on Earth, found in sand, emerald, quartz, clay, and glass. Just like sand and glass filter media, DE has a similar makeup, but it is thought of as the best swimming pool filtration method you can use.

Diatoms under the microscope!

When the DE sediment is ground down, it creates a fine abrasive powder with many uses in a wide range of industries such as food, agriculture, military, and even cat litter! DE is known to be the best media for water filtration because it is finer than sand and has a sponge-like structure better suited to capturing contaminants, with the ability to absorb impurities. DE can remove particles as small as 5 microns, for reference, a grain of sand is 1,000 microns! The DE used in pools is different from food-grade DE because it has been heat-treated to give the silica a structure that improves filtering.

DE is such an effective filtering media that it can even remove heavy metals such as copper, iron and manganese from your pool water. This is important because if you leave these metals in the water, chlorine will react to them and turn the pool water milky white (mild reaction), green (middle reaction), or brown (extreme reaction). Brown water has been known to stain the surfaces of the pool.

Pool Tip: When adding new DE to your filter cartridge, use ½ cup less than the instructions. This is due to the fact that there will be leftover DE in the filter even after cleaning. Excessive DE in the filter can cause a clogged skimmer and other issues.


When DE is added to the pool filter system, it coats the filter grid and as water passes over it, the DE captures microscopic debris in the water. Although you cannot see everything that DE is filtering, you will notice the difference in your sparkling clear water!

Swimming pool DE can be purchased with us here and our favorite brand is CelaPool. If you are searching for a replacement for your current pool filtration system - consider DE!

Read our other blogs on DE:


5 Steps to Change DE Filter Grid

How to Manually Clean DE Pool Filter