Can You Use Diatomaceous Earth in Water? The Important Differences
Yes, you can use diatomaceous earth (DE) in water, but the safety and efficacy depend entirely on the type of DE and your intended use. For applications like pool filtration, adding a special grade of DE to water is the standard procedure. In contrast, for garden pest control, a DE-and-water slurry is a popular application method, but the powder only works once the water has evaporated. Furthermore, some people consume a very specific food-grade DE mixed with water, though its health benefits are not well-supported by scientific evidence. The key takeaway is that the fine, abrasive particles that make DE effective also pose a serious inhalation risk, especially with the high-heat treated, crystalline filter grades. Always verify you have the correct grade for your project and take the proper safety precautions.
Food Grade vs. Filter Grade: The Crystalline Difference
The most critical factor when using diatomaceous earth in or around water is understanding the distinction between food-grade and filter-grade (often called pool grade). The primary difference is the concentration of crystalline silica, which is created by heat treatment.
- Food Grade DE: This type of DE is mined from freshwater sources and contains very low levels of crystalline silica (typically less than 2%). The particles are mostly amorphous, meaning their sharp edges are less harmful when consumed, though they can still cause lung irritation if inhaled. Food-grade DE is the correct choice for pest control, livestock feed additives, and purported dietary supplements.
- Filter Grade DE: This DE is heat-treated (calcined) to increase its crystalline silica content (around 60%) to improve its filtration efficiency. It is designed specifically for filtering liquids in applications like swimming pools and industrial processes. Ingestion or inhalation of filter-grade DE is highly dangerous and can lead to serious lung diseases, including silicosis.
Using Diatomaceous Earth in Water for Pest Control
For garden or home pest control, a wet application of food-grade DE is a common and useful technique. While DE is ineffective at killing insects when wet, mixing it with water allows for easier application in hard-to-reach or large areas.
- Creating a DE slurry: A typical ratio is about 4 tablespoons of food-grade DE per gallon of water. You must shake the mixture frequently during application, as the DE will settle at the bottom of the container.
- Application: A spray bottle or pressurized sprayer can be used to apply the slurry to plant leaves, patio cracks, or other surfaces. This is especially useful for targeting the undersides of leaves where pests like spider mites hide.
- How it works: Once the water evaporates, it leaves behind a fine, abrasive dust that kills insects by dehydrating them upon contact. This mechanical action, which damages their protective exoskeletons, means pests cannot build a chemical resistance. The powder must be dry to be effective, so reapplying after rain or heavy watering is necessary.
Using Diatomaceous Earth in Water Filtration
Diatomaceous earth filters are highly effective at removing extremely fine particles, down to 3-5 microns, from water. This is why they are a top choice for swimming pools, where they produce sparkling-clear water.
- Precoat application: A DE filter operates by first creating a thin, porous layer of filter-grade DE on a filter screen or grid. This is done by adding the DE powder into the skimmer or filter directly while the pump is running, creating a slurry that coats the grids.
- Filtration cycle: As water passes through this layer, the microscopic, fossilized diatom shells act as a sieve, trapping tiny impurities like dirt, algae, and some bacteria and protozoans.
- Backwashing: Over time, the DE cake becomes clogged with trapped debris and the pressure increases. The filter is then backwashed to flush the spent DE and contaminants out, and a new charge of DE is added to restart the cycle. It is crucial to handle the backwash water properly to prevent harm to pets, children, or the environment.
Consuming Food-Grade Diatomaceous Earth in Water
Some health and wellness trends promote the internal use of food-grade diatomaceous earth, often mixed with water or other liquids. Proponents claim it can help with detoxification, digestive health, and bone support due to its silica content.
- Preparation: Users typically mix a teaspoon or tablespoon of food-grade DE into a glass of water. Because DE does not dissolve, it must be stirred vigorously and consumed quickly to prevent it from settling.
- Scientific evidence: It is important to note that most health claims associated with consuming DE are largely anecdotal or theoretical and lack robust scientific backing from human studies. While food-grade DE is generally recognized as safe for consumption by the FDA in low concentrations, its efficacy as a dietary supplement is unproven.
- Risks: Some people report temporary flu-like symptoms during the initial 'detox' period. As always, a healthcare professional should be consulted before starting any new supplement regimen.
Comparison of Diatomaceous Earth Grades
| Feature | Food-Grade Diatomaceous Earth | Filter-Grade Diatomaceous Earth |
|---|---|---|
| Composition | Primarily amorphous silica (low crystalline silica) | High concentration of crystalline silica due to heat treatment |
| Best Uses | Household pest control (dry or wet/dry), garden insecticide, livestock feed additive, dietary supplement | Swimming pool filtration, industrial liquid filtration, brewing and winemaking |
| Water Application | Can be mixed with water for ease of application; must dry to be effective for pest control. Can be ingested in water. | Designed to be mixed into pool water or other liquids for filtration purposes. DO NOT INGEST. |
| Inhalation Risk | Still irritates lungs; use mask. Long-term risk is lower than crystalline. | High risk of lung disease (silicosis) if inhaled regularly. Wear proper PPE. |
| Safety for Pets | Relatively safe if food-grade, but avoid inhalation and ingestion of significant amounts. | Extremely dangerous. Never use around pets or allow ingestion. |
Conclusion
Using diatomaceous earth in water is a common practice, but it is not a one-size-fits-all solution. For pest control, a food-grade DE slurry provides an effective, chemical-free way to distribute the powder, but it must dry to work. For water filtration, filter-grade DE is a powerful medium for creating sparkling water, but it is toxic and must be handled with extreme caution, especially concerning inhalation and backwash water management. Internal consumption of food-grade DE is practiced by some, but its health benefits are not scientifically proven. Always prioritize safety by using the correct grade for the job and preventing inhalation, regardless of the application. For those seeking safer water filtration alternatives for pools, cartridge or sand filters exist.
Key Safety Precautions for Using DE in Water
- Choose the right grade: Always use food-grade DE for pest control, consumption, or any application involving contact with people or animals; use filter-grade DE only for designated filtration systems.
- Wear protective gear: Regardless of the grade, wear a dust mask or respirator to avoid inhaling the fine particles, which can irritate or damage the lungs.
- Prevent inhalation: When mixing DE with water, do so slowly and carefully to minimize airborne dust. Avoid applications that create large dust clouds.
- Work when it's dry: For pest control, remember that DE is only effective against insects when it's dry. Reapply a wet mixture after it has dried and lost its effectiveness.
- Handle backwash safely: When backwashing a DE pool filter, ensure the contaminated water is disposed of properly, not on lawns or near pets and children, as it can contain hazardous crystalline silica.
FAQs
Question: Can I drink food-grade diatomaceous earth mixed with water? Answer: Yes, it is widely considered safe to ingest small amounts of food-grade DE mixed with water, as it is largely unabsorbed by the body. However, scientific evidence for its purported health benefits is limited.
Question: Is there a difference between food-grade and pool-grade diatomaceous earth? Answer: Yes, there is a critical difference. Pool-grade DE is heat-treated to contain a high percentage of crystalline silica, making it dangerous if inhaled or ingested. Food-grade DE has very low crystalline silica and is safer for applications involving humans and animals.
Question: Will mixing diatomaceous earth with water make it ineffective for pest control? Answer: Diatomaceous earth will only kill insects once it is dry, as its mechanical action relies on dehydrating pests by damaging their waxy outer coating. The water mixture is merely for easier application, and the powder will become active again when the water evaporates.
Question: What are the inhalation risks associated with diatomaceous earth? Answer: All grades of diatomaceous earth pose an inhalation risk due to the fine, abrasive particles, which can irritate the lungs. Inhaling filter-grade DE, with its high crystalline silica content, is particularly dangerous and can lead to serious respiratory diseases like silicosis.
Question: Can I use a regular vacuum to clean up diatomaceous earth indoors? Answer: You should check your vacuum's instructions, as the fine particles can clog some vacuums or be blown back into the air. For carpets, a light application followed by vacuuming after a few hours is recommended, but a damp rag might be safer for non-carpeted areas.
Question: How does diatomaceous earth filter water in a swimming pool? Answer: In a pool filter, filter-grade DE is applied as a coating on porous grids. As water passes through this coating, the tiny, sharp fossilized diatoms trap microscopic impurities like dirt, algae, and bacteria, resulting in very clear water.
Question: Is diatomaceous earth safe for pets to be around? Answer: When used properly, food-grade DE is generally safe around pets, but direct inhalation should be avoided. Never use pool-grade DE for any purpose involving pets, and keep them away from areas treated with DE dust until it has settled or been cleaned up.
