Berkey Fluoride Filter (PF-2) FAQ

Each white cylindrical Fluoride Filter is six inches long and of 2.5 inches wide. When attached to the stems of the Black Berkey Filters the Fluoride Filters hang down into the lower chamber approximately 7.5 inches. The threaded hole side of the Berkey PF-2 Elements that attaches to the Black Berkey® Elements is 11mm.

No, it does not contain cyanuric acid. The fluoride filters are not treated with cyanuric acid. 

A “lock” condition may occur, where the water flowing through the upper filter and into the lower filter will stop flowing into the bottom chamber once the water level reaches the bottom of the fluoride filter.

The filters can be adjusted by either turning them more revolutions or less. To fix this, the fluoride filter needs to be loosened slightly so that enough water can escape to prevent pressure from building up within the post filter element(s). In other words a small amount of “burping” (spill) is necessary for the filters to perform properly. To obtain optimum flow without a lock condition and to not have excessive water leaking, adjust the tightness/looseness of the filters. The number of rotations is a guide. If it appears that too much water is seeping between the threads tighten it a bit more (careful not to over-tighten and damaging the interior screen). If the system air locks, then try loosening the filters by unscrewing slightly.

No, they do not replace the black filters. 

The Fluoride Filters are also called PF-2 elements. The “PF” in PF-2 stands for Post Filter. Without the Black Berkey Filters there's nothing for the filters to attach to. The Fluoride Filters do not remove or reduce all the same things as the Black Berkey Filters. 

The Black Berkey Filters fit into the base of the upper chamber with the threaded stems of the filters protruding through the holes in the bottom of the upper chamber. The fluoride filters screw onto these threaded stems so that they hang down into the interior of the lower chamber. The water flows from the upper chamber, through the Black Berkey Filters, into the Berkey Fluoride Filters and then into the lower chamber.

Our third-party laboratory testing indicates that the Black Berkey Filters reduce Arsenic and Fluoride up to 99.9%. Typically carbon based elements that reduce Arsenic and Fluoride begin to lose that ability rather quickly. This is likely the case with Black Berkey Filters, which means that their efficiency at removing Arsenic likely decline prior to the expected lifespan.

For that reason, a longer lasting solution for Arsenic and Fluoride reduction was developed. Replaceable Berkey PF-2 Fluoride and Arsenic reduction elements mitigate the loss of efficiency from the carbon filters. The media in a pair of Berkey Fluoride Filters can reliably remove Arsenic and Fluoride contaminants for up to 1,000 gallons, which is less than the life expectancy of the Black Berkey Filters. That is why they were designed to be replaceable!

The Black Berkey Filter’s job is to remove a wide variety of potential contaminants, while the Berkey Fluoride Filter’s job is to specifically remove Fluoride and Arsenic; contaminants that the Black Berkey Filters may begin to miss after extended use. Contaminant reduction is dependent on the presence of other competing elements in the source water. High levels of fluoride, arsenic, and heavy metals may reduce the capacity and efficiency of these elements.

No, not necessarily. The Berkey Fluoride Filters are best for city water that's been treated with Fluoride. Not all city water is treated with Fluoride. The Fluoride Filters aren't necessary if there's no fluoride to remove. However,