Incredible Minerals Today

Diatomaceous Earth: Why it’s still the best swim pool filter media

Posted by Niels Mastrup

Aug 27, 2014 9:01:00 AM


DE: An amazing prehistoric mineral

Diatomaceous earth (DE) is a common powdered filter media used in industry worldwide for a variety of filtration applications. It is a product that touches our everyday lives and most of us do not realize the importance and functionality of this gift from nature. It's used every day to purify everything from the water we drink, to waste water. DE is the workhorse of the industry clarifying nearly every type of liquid including beer, wine, juice, chemicals, edible oils (including extra virgin olive oil,) pharmaceuticals, chemicals, and many other important process liquids and food products.

So where does diatomaceous earth come from? DE is composed of the fused frustules of single cell plants called diatoms. They are considered the beginning of the food chain in our oceans and are responsible for sequestering much of the world’s atmospheric CO2. Simply put, without diatoms, life on earth would not exist as we know it today. The vast majority of today’s commercially available DE were formed during the Tertiary period of the Cenozoic era; approximately 3-12 million years ago.

How did DE start being used for swim pool filtration?

DE got its big break in Hollywood during the 1930’s while in production of the very popular Esther Williams’ “aqua musicals” swim-based movies. During production, the pool water where filming was taking place continuously needed to be replaced due to the tendency of the water to get cloudy, making the film cuts unacceptable. The studios enlisted the help of local engineers, who developed the first commercial swim pool filter. Following much experimentation with known and accepted technologies, they finally selected DE as the ideal media to keep the water sparkling clear, suitable for underwater filming.

Back in the day, the best water clarity was required to present clear images on the silver screen and DE filtration fit the bill. From those star struck days of movie glitz, pool builders quickly caught on to DE filtration as an essential tool to keep commercial and residential pools consistently sparkling clear. The beautiful pool images created demand and gave way to the rapid growth and popularity of the residential swim pool industry. DE filtration has been an integral part of this great American lifestyle luxury--the back yard pool!

How does DE work and why is it the superior choice for swim pool filtration media?

Simply put, DE is the highest performing filter media available at the lowest operating cost per season with equivalent clarity. Today’s modern residential pools are not just simply for swimming, they are a statement of your personality and style. Designs and features in today’s modern pools have evolved and highlight the beauty of the water itself with fountains and lights. This trend has heightened the need for brilliant water clarity to showcase these new features day and night. An illuminated pool at night will either showcase your pool’s brilliant water clarity or highlight the deficiencies in your filter system by reflecting light on particles not visible during the daylight. DE is clearly the choice for these demanding applications. It will consistency provide a crystal clear pool. Sand and cartridge filters can’t meet the level of brilliant clarity that DE can.

DE & safe swimming.

In recent years, we have seen many new filter media products come to the market place and tout themselves as a replacement for DE. Certainly there are alternatives but none better than DE. In 1993, following a tragic outbreak of cryptosporidium in Milwaukee, the New England Journal of Medicine published a study that investigated the best remedy for treating surface water contaminated with Cryptosporidium or Giardia, a terrible illness that makes you very sick and dehydrated. 403,000 people became ill and 104 people died, primarily the elderly and those with compromised immune systems. It was concluded that DE was the best and most effective treatment system to remove the disease-carrying protozoa from the source water at a 6 log removal efficiency. Another study conducted by the University of North Carolina confirmed the superior removal efficiency of DE in swim pool applications. Cellulose was not considered for either study because of its inferior solids removal efficiency. DE is simply more efficient at particulate removal efficiency verse any other available filter media commonly used in the pool industry. In the study titled “Removal of Cryptosporidium and Polystyrene Microspheres from Swimming Pool Water with Sand, Cartridge, and Precoat filters, by UNC, it was found that DE had a 99.4-99.996% effectiveness rating in pathogen removal efficiency. Cartridge filters showed only a 36% or less efficiency rating in removing pathogens. (James Amburgey, J Water Health. 2012 Mar;10, University of North Carolina)

Why does DE get a bad rap?

Dust – Diatomaceous earth is a natural, light weight mineral with very large percentage of void space. These are the primary reasons it is ideally suited for liquid filtration but it also makes the product prone to dust concerns. A simple, inexpensive dust mask addresses this health risk as does the application of some common sense and good work practices. When preparing to apply DE into your filter, it is recommended that the operator wear a dust mask and prepare a slurry of DE for addition to the filter system. Once DE has been wetted, the dust hazard is eliminated. Spills are easily cleaned up when washed away with water, avoiding any dust creation when swept up with a broom.

The bottom line? DE is still the “clear” choice when it comes to swim pool filtration. To produce sparking clear water and the cleanest, safest pool water available, there’s nothing like the filtration properties of the ancient diatoms – diatomaceous earth.

For more information on DE for swimming pools, visit or email me directly at

Niels Mastrup, Director of Filtration Technology

Topics: Filtration, swim pool


About this blog

Incredible Minerals Today gives readers insights and information about new exciting uses for diatomaceous earth, perlite and clay around the world today, plus the latest information about EP Minerals. 

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