Diatomaceous Earth

Diatomaceous Earth: Calcined vs. Non-Calcined

Diatomaceous earth can be calcined or non-calcined. The difference between the two is very important depending on what purpose the DE is being used for.

Calcined diatomaceous earth has been treated at a temperature above 1000 ºC. The purpose of this is to further harden the exoskeletons of the diatoms in order to create a better filtering agent. This process causes the amorphous silica that makes up the exoskeleton of the diatom to turn in to crystalline silica. This is a benefit if the diatomaceous earth is to be used as a filtering aid (for example, in a pool filter), however crystalline silica can be toxic to humans and animals when inhaled. Calcined diatomaceous earth is not used for animal feed and is not food grade.

Natural diatomaceous earth is non-calcined meaning that it has not been treated at a high temperature. The amorphous silica remains in its natural state and is not considered harmful to animal or human health. Diatomaceous earth products, such as Red Lake Diatomaceous Earth, are required to contain less than 1% Crystalline Silica. Calcined DE products however, may contain up to 70% Crystalline Silica!

Diatomaceous Earth

Diatoms: Interesting Facts

Diatomaceous earth is made up of tiny, single-celled organisms known as diatoms. Diatoms have been studied for hundreds of years and have proved to be amazing organisms, serving various functions in both life and death.

Diatoms were discovered in 1702 by Anton van Leeuwenhoek. It was thought that these organisms were tiny animals however, in the 19th century biologists concluded that diatoms are in fact plants, due to the fact that they perform photosynthesis.

Many years ago, in a June 1979 Edition of National Geographic, Richard B. Hoover published an intriguing article about his research on diatoms. Richard traveled the world, examining diatoms and collecting new species. Throughout his travels he saw and learned many things about these extraordinary organisms. Here is a summary of some of the most interesting facts revealed in Richard’s report.

One of the most interesting discoveries mentioned in this paper occurred while Richard was studying a diatom collection in Belgium. He added water to diatoms that had been dried on paper in 1834. Much to his surprise, they were revived by the water and began to swim around – after nearly 150 years!

There has been found to be more than twenty-five thousand species of diatoms, none of which have the same shell. They exist in large numbers in most bodies of water throughout the world. In fact, just one liter of seawater can contain as many as ten million diatoms! Diatoms are the most abundant type of phytoplankton, with the greatest numbers existing in cold oceans.

Diatoms can thrive wherever there is light, water, carbon dioxide, and necessary nutrients. They can be found all across the world, from cold Rocky Mountain streams to thermal springs in Arkansas to polluted pools and road side ditches. In some cases diatoms can even live out of the water. In moist conditions, they are able to live in topsoil, or attached to moss, tree trunks and even brick walls. Diatoms are very resilient and can endure lengthy droughts.

Diatoms vary greatly in size, with the largest measuring only one millimeter across. Two basic forms of these organisms exist. They are known as Centrales and Pennales. Centrales have markings, rows of pores or spines, that exist in perfect symmetry. Most often Centrales live in oceans and are wheel-shaped. They can typically be found drifting near the surface, basking in sunlight and absorbing nutrients. The other type is known as Pennales. Pennales tend to be elongated and have markings in bilateral rows. For the most part, Pennales live in fresh water streams, swamps, ditches, or on the bottoms of shallow regions of oceans and estuaries.

On the tidal sand flats of Cape Cod exists one of the most fascinating species of diatoms. Known as Hantzschia virgata, this species bury themselves in the sand when the tide is. Just after the tide goes out, the diatoms glide to the surface in order to sunbathe. What is so remarkable about this species is that they know precisely when to bury themselves back in to the sand, retreating just moments before the tide returns, saving themselves from being washed out to sea. In fact, it was discovered that even after keeping these diatoms for weeks in a laboratory, under constant light, their impeccable timing remained constant, as they continued to dig in and out of the sand with such amazing accuracy that their actions could be used to predict the tide.

Diatoms are also impressive shell builders. They transform dissolved silicon into a silica almost identical to the gemstone opal. Diatoms contribute enormous amounts of oxygen to our atmosphere and even offer various functions when dead, as diatomaceous earth.

Huge numbers of diatoms die and sink to the bottom of river, lake and ocean beds. In some areas sea floors can be covered in a layer as deep as 984 feet (300 meters)! Over many years these layers of dead diatoms fossilize and become rich deposits of diatomaceous earth, or diatomite.

Image by Chandler Abraham

Diatomaceous Earth

Diatomaceous Earth vs. Zeolite

Zeolite and diatomaceous earth are both naturally occurring materials that have a variety of purposes.

What is Diatomaceous Earth?

Diatomaceous earth (DE) is made up of the fossilized exoskeletons of tiny single-celled organisms known as diatoms and is very porous at the microscopic level.

Diatomaceous earth deposits can be derived from both fresh and salt water sources. There are two main types of DE – food or feed grade and pool grade. Diatomaceous earth derived from a freshwater source and that meets specific heavy metal content regulations is considered “food grade” by the US Department of Agriculture.

What is Zeolite?

Zeolites are crystalline, hydrated aluminosilicates with very rigid structures. Compositionally, zeolites are similar to clay minerals however, their special crystalline structure remains rigid in water.

While zeolite is a naturally occurring material it can also be manufactured. Currently over fifty different natural zeolite minerals have been identified and over one-hundred zeolites have been synthesized.

Diatomaceous Earth Uses

Diatomaceous earth is commonly used in livestock feed as an anti-caking agent and pelleting aid. Diatomaceous Earth is also known to work well as a natural insecticide.

Zeolite Uses

Each zeolite has a different size and function.

All zeolites are molecular sieves, meaning that they selectively absorb molecules on the basis of shape, size or electrical charge. The cations in zeolite are very loosely bound, allowing them to be exchanged with other cations or molecular water. Each different type of zeolite has the ability to exchange a particular cation in its chemical makeup for another cation.

Zeolites (particularly clinoptilolite) are often added to animal feed and function much the same as food grade diatomaceous earth. Much like DE, zeolite must be added to feed in controlled amounts.

Zeolite is also known to work as an insecticide. Due to its high ion exchange and adsorption capacities, natural zeolite, specifically clinoptilolite, is an effective carrier of herbicides, pesticides, and fungicides. As well, zeolite is often used in laundry detergent and water softeners due to the fact that it can release sodium and potassium in exchange for calcium and magnesium.

Most commonly, however, zeolite is used for ammonium-ion removal in waste stream treatment, sewage treatment, pet litter and aquaculture, as odor control, for heavy metal ion removal from nuclear, mine and industrial wastes and in agriculture as a soil conditioner, fertilizer extender and as an animal feed supplement.

It is very important that when utilizing diatomaceous earth and/or zeolite that you use the proper type.

Only food or feed grade diatomaceous earth should be used as an insecticide and in animal feed. Food grade diatomaceous earth meets very strict regulations in terms of crystalline silica and heavy metal content, making it safe for animals to consume.

It is important to note that there are several types of zeolite (including erionite and some mordenite) that are fibrous in nature and may be classified as asbestos-like materials. As well, crystalline silica commonly occurs in zeolite deposits and finely ground products may contain more than 0.1% crystalline silica that is small enough to inhale. It is therefore important that the proper type of zeolite be selected for your purposes.


Donald D. Carr, “Industrial Minerals and Rocks”, 6th Edition, Society for Mining, Metallurgy, and Exploration, Inc., 1994

Diatomaceous Earth

Food Grade Diatomaceous Earth as a Soil Amendment?

Food grade diatomaceous earth is often used in the garden as a natural pest control substance. However, many studies have also been conducted to analyze the effect that diatomaceous earth has as a soil amendment.

These studies have shown promising results, suggesting that diatomaceous earth may significantly enhance nutrient retention and moisture retention in soil.

Southern Cross University

A study conducted at Southern Cross University in Australia tested soils amended with fertilizer and various rates of diatomaceous earth, with the fertilizer acting as a control substance.

The study found that with the addition of DE, the nutrient level of the soil was significantly improved and the leaching of any fertilizer was greatly reduced. The results of this study suggest that the addition of DE to soil amended with fertilizer may allow for more efficient use of fertilizer and reduce the impact that fertilizer has on the environment through leaching.

As a result of this study, it was also discovered that food grade diatomaceous earth improved the retention of moisture in potting mix, soil and sandy soil by holding a greater bulk quantity of water and drying at a slower rate. As well, it has been shown that the addition of DE to soil can increase drought resistance when added to the sand of golf putting greens.

Do you find that our diatomaceous earth works well as a soil amendment? Share your story with us using the form below or email us at

Diatomaceous Earth

Consumer Reports: Diatomaceous Earth for Rescue Animals

The Imminent Danger German Shepherd Rescue in Greenville, Tennessee is a no-kill shelter run by volunteer members. The organization rescues and rehabilitates abandoned German Shepherds that have been neglected and mistreated and helps them to find loving, caring homes. Using a holistic approach, the Imminent Danger German Shepherd Rescue has been able to save the lives of many dogs affected by abuse and poor nutrition.

Recently the rescue helped save the life of a dog named Luxor whose body was 75% covered in Demodex mange. Luxor received daily food grade diatomaceous earth baths for over 2 weeks. Nutraceuticals were also added to his diet and within 2-3 weeks he began to grow back his fur. Currently, Luxor (now know as Duke) is a healthy, 95 pound, 10 month old pup. He will be entering the Canine Good Citizen Training and eventually Therapy Dog Training to become a therapy dog that will visit nursing homes and hospitals.

“I’ve also used the DE by mixing [it] up into a slurry, kind of thick and putting it on hot-spots on dogs, it takes the ‘heat’ and ‘itch’ out”, says Deborah, founder of the Imminent Danger German Shepherd Rescue. We rarely have much of a flea problem, if fleas are on a dog, it’s usually a new rescue and we treat [them] quickly. [We] make a dip of DE and water and pour [it] over the dog to kill the fleas and ticks. We also used DE, 1 cup to 1 gallon of water, on our vineyard this year. It seemed to keep the bugs at bay and was far more effective and safer than using cancer causing chemicals.”

The Imminent Danger German Shepherd Rescue strives to provide comfort and assistance to animals in need and is continuously searching for foster homes and forever families to help them do so. Please visit for more information.

Diatomaceous Earth

A Real Miracle: Duke the German Shepherd

Duke (formerly known as Luxor), a purebred German Shepherd, came to the Imminent Danger German Shepherd Rescue Center back in June/July of 2011. He was pulled from a shelter in a nearby county and at the time was very, very sick. He was 75% covered in Demodex mange, his body covered in bleeding, oozing, puss-filled sores. The shelter had put a chemical on Duke and the Imminent Danger German Shepherd Rescue was told not to bathe him. Upon arrival at his new home, Duke was bathed in food grade diatomaceous earth and continued to be bathed in DE everyday for over two weeks. He was also fed nutraceuticals and within 2-3 weeks Duke began to grow back his fur.

Rescued German Shepherd

Day 1 at the Imminent Danger German Shepherd Rescue Center

German Shepherd at Imminent Danger German Shepherd Rescue Center

Just 16 days after being brought to the Imminent Danger German Shepherd Rescue Center

Healthy German Shepherd playing outside

A healthy Duke playing outside

Thanks to the help and support of the Imminent Danger German Shepherd Rescue, Duke is now a healthy dog. He has completed his Canine Good Citizen training and Therapy Dog training and will become a therapy dog that will visit nursing homes and hospitals. “He most definitely has the temperament for it. I knew it from the moment I met him, calm sweet boy, you don’t get pups in everyday who have that disposition, but he’s got it and will make a great therapy dog”, says Deborah, the founder and operator of Imminent Danger German Shepherd Rescue. “He’s got a great home, and has great opportunities and will be a true blessing to others in his service.”

Diatomaceous Earth

How Does Diatomaceous Earth Work: Microscopic Images

Diatomaceous Earth is composed of the fossilized exoskeletons of tiny organisms known as diatoms. These fossilized diatoms have very sharp edges allowing the diatomaceous earth to kill insects by lacerating their outer shells and dehydrating them.

When crawling insects come in contact with food grade diatomaceous earth it is much like crawling across shards of broken glass. The insects’ movement across the DE helps the razor sharp edges to lacerate its body.

In the pictures above (taken by Dean W. Blinn and J. Norman Grim) you are able to see just how diatomaceous earth works.

The image to the left shows food grade diatomaceous earth piercing the rear of a cockroach. In the image to the right, you are able to see DE particles lacerating an insect under extreme magnification.

Diatomaceous Earth

Diatomaceous Earth for Grape Growing?

Many people find food grade diatomaceous earth to be a helpful soil amendment that works well to retain moisture and nutrients in soil. While the product is not currently registered for this use, there have been many studies conducted to explore the possible benefits of the addition of DE to soil. In fact, a study conducted in Australia concluded that diatomaceous earth showed significant benefits when used for growing grapes. Diatomaceous earth was mixed in to the soil at a rate of 100 kg/ha (approximately 88 lb/acre) and yielded the following results:

    • Increased water holding capacity

    • Better uptake of calcium and phosphorous in the grape vines

    • Bigger V-shaped bunches

    • Hardier grapes with reduced fruit split

    • Increased size of root zones

    • Higher soil organic carbon levels

    • Reduced requirement for superphosphate

    • Increased silicon levels

    • Increase in plant available Calcium, Phosphorous, Magnesium and Potassium levels at early
       growth stage as well as increased Potassium levels at flowering and Magnesium levels at
       post harvest

Please note: as food grade diatomaceous earth is not currently registered for human consumption, it is important to thoroughly wash any foods meant for human consumption that may have come in contact with DE.

Let us know how you use diatomaceous earth and what results you have seen! Email us at or use the contact form below.

Image by roblisameehan

Diatomaceous Earth

Diatomaceous Earth Particle Size: Choosing the Right Granulation

Diatomaceous earth is available in a variety of different granulations. While they are all composed of the same ingredients, it is important to select the proper granulation according to the purpose you wish to use it for.

Below is a list of DE granulations and the purposes for which they work best:

Powder Granulation

    • As insect control

    • In grain bins

    • In animal feed

    • Processing aid – anti-caking agent

Fine Granulation

    • Mixed in animal feed

Granular Granulation

    • Mixed in feed

    • For odor control

Diatomaceous Earth

Diatomaceous Earth in Animal Feed: Affects on Meat, Dairy and Eggs

Red Lake Food Grade Diatomaceous Earth is OMRI listed (Organic Materials Review Institute) for use in organic production and is safe to use with all animals (except reptiles, as it may dry out their skin).

No diatomaceous earth residue has been found in animals (or their offspring or milk) that have consumed Red Lake Earth. In fact, a study was conducted to test for any absorption of diatomaceous earth into milk produced by cows that had consumed it in their feed. DE was mixed into the cows’ feed at a rate of two percent. The results of this study found “no evidence of absorption or any residue of the product in the milk”. Diatomaceous earth can also be contained in the feed of layers, as well as animals produced for meat, without any residue transferring to the resulting products.

Meat, eggs and milk produced by animals that ingest food grade diatomaceous earth will not contain DE residue and are considered safe to consume.