It's also well known because most public tap water is fluorinated. Fluoride started being added to public water in the 1940s in the united states to improve dental health. The fluoride that goes into two-thirds of American households mostly comes from phosphorite rock. 

Fluoride in Drinking Water Controversy

The fluoridation of public water is controversial because it may be an unnecessary additive. Fluoride has been deliberately added to several municipal water supplies for over sixty years now. The communicated reason fluoride was and is added to public water was to improve the dental health of the public, which then, in turn, improves the overall health. Fluoride indeed does improve the health of teeth, however, there are other means of using fluoride for health benefits. Consuming it in drinking water is not the only way to get it into the human body, in fact, drinking it may be the cause of adverse health effects. Small doses in toothpaste, mouth rinse, etc, that are then spat out, provide the benefits of strengthening tooth enamel, without the detriments of deteriorating bones by drinking an unknown dosage. 

One claim against adding fluoride to public water is the belief that it is mass-medicating a population without consent. Fluoride is added for health reasons, not for disinfecting, such as the addition of chlorine to water. For this reason, speculators question how can the dosage be measured? Medications are prescribed by a case-by-case basis, based on weight, age, and other factors. Additives not taking those characteristics into consideration could be dangerous and cause serious harm. It also doesn't account for high-consumption water users, such as athletes, laborers, or those with kidney diseases. The more water drank equals the more fluoride consumed. 

The health and hygiene benefits of applying fluoride directly to the surface of teeth are well known and seldom disputed. The dispute begins with fluoride that has been added to drinking water only comes in contact with the teeth for a very short amount of time and in a very diluted form. After this contact, the fluoride is then swallowed and the human body is subject to the well-known ill effects of the fluoride compound for hours after ingestion. Critics claim that in this age of high fluoride toothpastes that are correctly applied directly to the surface of the tooth, the benefits of fluoride in the water supply are negligible and quite possibly unnecessary.  

How Does Berkey Filter Fluoride From Water?

The Berkey Fluoride Filter uses a time-tested method that was developed to reduce fluoride in your drinking water. Berkey developed this filter to address the concerns of the many who find the practice of adding fluoride to drinking water questionable or unacceptable. Berkey Filters allows you to make this decision about your health yourself by reducing the amount of fluoride in your water by up to 97%. 

The proprietary media inside the filter is a new and improved high yield aluminum oxide especially formulated for the removal of fluoride and arsenic from drinking water. This media has an unusually high surface area of more than 350 sq.m./gram of material which allows more efficient removal of the fluoride and arsenic ions. This high surface area is enhanced by controlled development of the pore size distribution from 30 Angstroms to 100 Angstroms, providing greater accessibility to the surface active sites through bulk diffusion. Uniform particle size low silica content, and high purity, are characteristic of the new and improved media blend. The extremely low silica content significantly reduces the tendency of the silica to form silicon tetrafluoride which reacts with both the media and the pipes leading to clogging and corrosion problems. 

The proprietary media in the Berkey Fluoride Filters will remove any types of inorganic fluoride salts including calcium fluoride and sodium fluoride. All fluoride salts are soluble in water. So it does not matter what fluoride salts that are in the water, fluoride is present as an anion where the media will absorb fluoride ions in water. The Black Berkey Filters are well designed and extensively tested to use the best technology to filter out unwanted things.  

Technical Information

Testing was performed with a flow rate of fewer than 11 liters per minute per cubic foot of the Berkey filtering medium at 20 - 30 parts per million (ppm) of the ion in the solution liquid. Results of < 1ppm of the fluoride ion in the effluent were typical for the filter media (up to 97% reduction). Under optimum laboratory conditions, effluent concentrations of less than 50 parts per billion (ppb) were readily achieved which equates to a >99.75% reduction.

Activated alumina in the filter media ingredient list--is that the same thing as aluminum?
Our PF-2 filters reduce fluoride and arsenic in your water using the media aluminum oxide (aka activated alumina). As a consumer, it’s important to know that pure aluminum and aluminum oxide have vastly different characteristics. Pure aluminum is water-soluble, is highly reactive, and is associated with negative health effects. By contrast, aluminum oxide is not water-soluble; is inert, is very stable, and is not associated with negative health effects. 

Fluoride Filter Lifespan

It is recommended that each set of two Berkey Fluoride Filters should be replaced after 1,000 gallons, or one year--whichever comes first. Example: A Big Berkey System (two gallon capacity) refilled two times per day, four gallons of water are used per day. Under these conditions, the Fluoride Filters would last 250 days (1000 gallons ➗  by 4 = 250) or a little over eight months. The actual replacement period for the Fluoride Filters depends on the amount of water used and the presence of other competing contaminants in the source water. High levels of arsenic, fluoride, and heavy metals may negatively affect the efficiency and capacity of the filters.

The best way to gauge when to replace the Berkey Fluoride Filters is to do the following:

1) Keep a track of how many times per week you need to refill your system.

2) Then multiply that figure times the capacity in gallons of your particular system (for example the Berkey Light system is 2.75 gallons) to determine Total Gallons Used Per Week.

3) Finally divide the Total Gallons Used Per Week into the 1,000 gallons and that will tell you how many weeks before the filters should be replaced.

4) Next calculate the future date for replacement (52 weeks per year) and write that date on a sticker and attach it to the bottom of your system for future reference. If you have been using your fluoride reduction filters for some time now, you can still use the above formula to determine when to replace the filters. Just count forward from the date you purchased your filters.