Black Berkey Filter Knowledge Base

Do the Black Berkey Elements filter out aluminium sulfate?


The Black Berkey™ purification elements have been tested to reduce Aluminum to greater than 75%. While we do not have specific testing for Aluminum Sulfate, most likely the Aluminum molecule would be stripped out, leaving sulfate.

The sulfate ion is a polyatomic anion with the empirical formula SO2-4. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many are prepared from that acid.
Aluminum sulfate is a chemical compound that is sometimes referred to as sulfuric acid, aluminum salt, or cake alum. It has a wide variety of applications, including waste treatment, water purification and paper manufacturing.

Aluminum sulfate is an odorless, white, or off-white crystalline solid or powder. It is hygroscopic, which means it has the ability to absorb and hold water molecules from the surrounding atmosphere.
Aluminum sulfate is used in water purification and as a mordant in dyeing and printing textiles. In water purification, it causes impurities to coagulate which are removed as the particulate settles to the bottom of the container or more easily filtered. This process is called coagulation or flocculation.

In reality, small amounts of Aluminum Sulfate in your pre-filtered water is actually a good thing, as it will help other impurities in your water to bond together with the Aluminum Sulfate and reduce the overall TDS (Total Dissolved Solids) in your water before it is filtered through the Black Berkey elements.


Do your filter elements reduce fluoride in the water?


No, in order to reduce fluoride in your water you will need to use post filters that work in conjunction with the filters in your system. We have two types, the PF-2, which are used in conjunction with the Black Berkey purification elements, and the PF-4 filters that are used in conjunction with our ceramic filters.


I did a TDS reading on the purified water and was surprised to find that the reading was about the same with the purified water as it was with the unpurified water. Is my system working properly?


Yes, a TDS meter measures only Total Dissolved Solids or minerals; dissolved solids are simply dissolved minerals in an ionic form. A TDS meter does not measure the amount of biological and chemical contaminates. Black Berkey™ elements are designed to leave in your water the healthful and beneficial minerals and to extract only the unwanted heavy metals such as lead and mercury as well as sedimentary minerals such as iron oxide and aluminum. Therefore, your TDS reading will not change much unless you have a significant amount of heavy metals or sedimentary minerals in your water.


What are the Black Berkey purification elements made out of and how do they work?


Without getting too complex, several methodologies are utilized by the Black Berkey purification elements. The elements are composed of a formulation of more than a half dozen different media types constructed into a very fine matrix creating millions of micro-fine pores. The pores are so small that pathogenic bacteria, cysts, parasites, sediment and sedimentary minerals are not able to pass through them. The media formulation both “absorbs” some contaminates and “adsorbs” other contaminates. Next, heavy metals ions (mineral molecules) are extracted through an Ion exchange process where they are essentially electrically bonded to the media. Finally, our filter elements are designed such that each water molecule can take several minutes to pass through the filter elements whereas these molecules passing through other filtration systems pass through those filters in literally microseconds. The longer the water molecules are in contact with any media, the greater the removal of the various contaminates.

  • Black Berkey™ Purification Elements are more powerful than any other gravity filter element currently available. The micro-pores within the cleanable Black Berkey™ purification elements are so small that pathogenic bacteria are simply not able to pass through them.
  • Black Berkey™ purification elements are so powerful, they can remove red food coloring from water without removing the beneficial minerals your body needs. Virtually no other filtration element can duplicate this performance.
  • The powerful Black Berkey™ purification elements also remove or reduce viruses, pathogenic cysts, parasites, harmful or unwanted chemicals such as herbicides and pesticides, VOCs, detergents, organic solvents, cloudiness, trihalomethanes, silt, sediment, heavy metals, foul tastes and odors, yet they leave in the healthful and beneficial minerals that your body needs and….
  • Because Black Berkey™ purification elements fit most gravity flters, existing gravity filtration systems can be upgraded. This vastly improves their ability to remove unwanted contaminates.

VIRUSES >99.999%

Exceeds Purification Standard (Log 4):

MS2 Coliphage – Fr Coliphage


Exceeds Purification Standard (Log 6):

Raoultella terrigena

TRIHALOMETHANES – Removed to >89.8%

(Below Lab Detectable Limits):






Removed to below Lab Detectable Limits:

Chlorine Residual (Total Residual Chlorine)

Volatile Organic Compounds (VOCs)

Removed to below Lab detectable limits



1,1,1-Trichloroethane (TCA)




1,1-Dichloroethane (1,1-DCA)

1,1-Dichloroethylene (1,1-DCE)






1,2-Dibromo-3-chloropropane (DBCP)


1,2-Dichloro-1,1,2-trifluoroethane (CFC 123a)











2,4,5-TP (Silvex)



2-Butanone (MEK)




3,5-Dichlorobenzoic Acid












Aldicarb Sulfone

Aldicarb Sulfoxide




Aroclor (1016, 1221, 1232, 1242, 1248, 1254, 1260)







Bromoacetic Acid










Carbon Tetrachloride




Chloroacetic Acid










Dacthal Acid



Dibromoacetic Acid

Dibromochloropropane (DBCP)




Dichloroacetic Acid

Dichlorodifluoromethane (CFC 12)








Disulfoton Sulfone

Disulfoton Sulfoxidea





Ethylene Dibromide (EDB)







Halo acidic Acids (HAA5)


Heptachlor Epoxide


Hexachlorobutadiene (CCC)



Isopropylbenzene (Cumene)

Lindane (Gamma-BHC)





Methyl Paraoxon

Methyl tert-Butyl Ether (MTBE)




MGK 264





























Tetrachloroethylene (PCE)

Tetrahydrofuran (THF)








Tribromoacetic Acid

Trichloroacetic Acid

Trichloroethene (TCE)


Trichlorofluoromethane (CFC 11)



Vinyl Chloride


Aluminum (>75%)

Antimony (>97.5%)

Barium (>80%)

Cadmium (>99.5%)

Cobalt (>95%)

Chromium (>95%)

Chromium 6 (>99.85%)

Copper (>95%)

Lead (>97.5%)

Mercury (>98%)

Molybdenum (>90%)

Nickel (>95%)

Vanadium (>87.5%)


Arsenic (>99%)

MBAS (>96.67%)

Nitrites (>95%)

Selenium (>97.5%)

Thallium (>99.5%)

Rust, Silt, Sediment, Turbidity, Foul Taste and Odors


Will a Berkey water filter work with softened water?


The Black Berkey purification elements are designed to remove heavy metals, but will not remove mineral salts, which are added by the water softener. We highly recommend that you obtain pre-softened water to use in your Berkey water filtration system.

You can use one of our purification systems on a regular basis by bypassing your water softener to get your drinking water. Most water softeners have a bypass valve or way to get water before it passes through your softener.

This is where you can obtain drinking water to run through our purification system.



I have found that when I boil the water or freeze it into ice cubes, I sometimes get little white floating things in the water. What is this?


With respect to the little white floaters in the water, it is not bacteria but rather a problem that sometimes occurs with hard (heavily mineralized) water. When the PH level of the purified water is raised, the acidity of the water goes down and the water is no longer able to hold as many minerals in solution. When this happens the minerals begin to precipitate out over time and depending on the mineral composition they will either sink to the bottom or float to the top. This process is known as flocculation and the precipitated minerals are usually referred to as “white floaters”. The bottom line is that this is nothing to be concerned about, the white floaters are minerals that were already in your water; they are now simply visible whereas they were previously invisible due to their suspension in an ionic form.



It appears that there is a slight dimple in one of my Black Berkey a elements, is this element flawed?


No, The Black Berkey purification elements are about twice as thick as are standard gravity filter elements. This is a built in redundancy or overkill, if you will. The minor dimple in the filter should not cause any decrease in the elements efficiency. However to check its performance, make sure the wing nuts are on tight and do the following:

Test your filters by filling the upper chamber with water then add a tablespoon of red food coloring for every gallon of water within your upper chamber. If the red food coloring is removed entirely, your elements are working properly. If not, check to make sure that the wing nuts on your elements are securely tightened then re-run the test.



It appears that there are chalk markings on my Black Berkey elements, is this element flawed?


No, The Black Berkey purification elements on a rare occasion may have chalk markings on them that are nothing more than production lots or numbers. While we strive to make sure each and every element looks the same, occasionally elements with these markings slip through our rigid quality control process. They will have no impact of the element’s performance and can be wiped off with a wet cloth or scrubbed off with a scrub pad.


It is time for me to replace my filter elements but I have a different brand name of gravity filter. Will the Black Berkey elements fit my system?


Yes the Black Berkey purification elements are interchangeable with other gravity systems and the PF-2 filters can be used as well.



What is the Micron Rating of the Black Berkey purification elements?


With respect to the micron rating, we do not use or publish a micron rating for the Black Berkey elements for the following reasons.

There is much confusion with respect to nominal and absolute micron ratings. An absolute micron rating is one that states the maximum pore size expected within an element. The nominal micron rating is the average pore size within the element. This means that if 90% of the pores are .02 microns and ten percent are 2 microns, one could claim the nominal micron rating as .2 microns, which would imply that pathogenic bacteria and parasites would be totally removed. But in reality the bulk of the water would channel through the larger 2-micron pores and thereby allow both bacteria and parasites to pass through. Therefore a nominal micron-rating claim can be very misleading.

With respect to the absolute micron rating, there is also confusion because there are two different standards to determine absolute; in the US the standard is 99.9% removal, but the international standard in 99.99% removal or 10 times greater removal.

Clever marketers of products can use the confusion over the above differences to make product “A” appear to be better than product “B” when product B may be far superior in reality. For example, we used to report an absolute rating using the international standard because we have a large international customer base. Several years ago we published a rating on our ceramic filters. A particular company began to publish that our elements were .9 microns whereas theirs were .2 microns. However, our micron rating was based on absolute (international) while theirs was based on a nominal(US)rating. When tested at Spectrum Labs, it was found that at the .2 to .3 microns range our filter removed more particulate than the other brand. Unfortunately many people make their purchasing decisions based on a micron rating that can be legitimately distorted and to a significant degree.

We soon became weary of trying to explain the above to our customers and so we decided not to participate any longer in publishing a micron rating. Rather, we think an absolute pathogenic bacteria removal rate is a far better gauge because it is far more difficult to abuse. Based on that criterion, the Black Berkey™ elements remove greater than 99.9999999% of pathogenic bacteria such as E.coli. To our knowledge, no other personal filtration element can match that capability. In fact, the Black Berkey elements are so powerful, they are unique in their ability to mechanically remove red food coloring from water.



I have been using my system for about six months and the flow rate has slowed down considerably. Do I need to replace the elements?


No, unlike other filtration elements Black Berkey purification elements are re-cleanable. What typically causes the filters to drip slowly is turbidity and sediment clogging the micro-pores of the purification elements. Simply remove the elements from your system, scrub the exterior of each element with preferably a white ScotchBrite pad or stiff toothbrush. Simply scrub a section of the filter until you see a bit of black on the white pad then move to the next section. It’s simple to do and takes less than a minute. Then re-prime each element and re-install them. Your problem should now be fixed.



How often do the Black Berkey purification elements need to be replaced?


Each element has an expected life of 3,000 gallons or 6,000 gallons for a set of two.



What is the shelf life of the Black Berkey purification elements?


The shelf life of the Black Berkey elements is indefinite. In other words they will last until you need them. We would advise however, if you intend to store them for a long period of time, that you store them in a zip-lock bag. This is because they are powerful enough to absorb contaminants from the air, which could reduce their expected life if you have a lot of airborne contaminants in the area in which they are being stored. A zip-lock back will prevent the above from occurring.



How do I prime the Black Berkey Purification Elements, in the field, when water pressure is unavailable?


The micro pores on the Black Berkey purification elements are extremely small, in fact they are small enough to filter red food coloring out of water. The benefit from having such extremely small pores is greater efficiency at removing pathogenic bacteria and other contaminates. The downside is that too much water tension can require that the purification elements be primed before they will flow properly. When you receive the purification elements, they are dry and air is trapped within the tiny micro fine pores. In certain parts of the world, water has more water tension than in other places and this can change from season to season. The higher the water tension, the more difficult it is for the water to force the air out of the micro fine pores using gravity alone. The pores that have air trapped within them do not allow water to pass through and therefore become an inaccessible passage for the water. This then can cause the system to either filter very slowly or not at all.
Before traveling to the field or using the system in an area without water pressure, we recommend that the purification elements be primed using the priming button method. If water pressure is not available to use the priming button method, the elements can be field primed approximately 50-75% by using the below method. In other words by using this method, the elements will not purify as fast as they will by using the priming button method however they will run significantly faster than if the elements have not been primed at all.

The field priming method is as follows:

  1. STEP 1: Fill the lower chamber with water, then place the purification elements into the water in the lower chamber, upside down with the stems facing upward. Put a ceramic coffee cup (or something else that will hold them under the water) on top of each purification element stem to force the element down under the water. Or, install the elements upside down in the upper chamber so that the elements are on the exterior of the bottom side of the upper chamber facing downward. Then place the upper chamber onto the lower chamber so that the filters are forced into the water within the lower chamber. Let the purification elements soak in the water for 30 to 60 minutes until they fill up with water. NOTE: Make sure that the opening in the stems of the purification elements are not underwater as the water must be forced through the pores of the element and not allowed to enter the element through the hole in the stem.
  2. STEP 2: When the inside of the purification elements are full of water they will be significantly heavier. Next, assemble the purification elements into the upper chamber while keeping the stems of the elements facing upward. It is important to keep as much water on the inside of the purification elements as is possible. Next, fill the upper chamber with water as quickly as possible. Hint: the fastest way to fill the upper chamber is to pour the water from the lower chamber into the upper chamber. Then place the upper chamber onto the lower chamber.

When the purification elements have water within the bore (inside core), more force is generated to draw water through the purification elements. This is because the water that drips out of the purification element also hydraulically pulls new water into the element as it begins to work like a siphon. Thus, in addition to the “Push” of gravity, there is also a hydraulic “pull” and this drastically improves the ability of the water to force the air from the micro pores. The above method is less efficient than priming the purification elements with the priming button but should be about 50-75% effective in clearing the blocked micro pores.

Let the water from the first purification cycle that is collected in the lower chamber run to waste. Next, refill the upper chamber with water. Your Black Berkey elements are now FIELD primed and your Berkey water filter is ready for use.

Note: If the water used to field prime the elements is from a contaminated or suspect source, if possible use a container other than the lower chamber to immerse the elements. If this is not possible then use the water that collects in the lower chamber from the first purification cycle to make a soapy dishwater. Then wash thoroughly the inside of the lower chamber and discard the soapy water. Next, purify more water and use it to rinse any remaining soap from the lower chamber. Your Berkey water filter is now ready for use.



I just purchased a Berkey Water Filter but didn’t receive a priming button. Instead, I think I received an extra black washer in the box. The instructions say to use the tan colored priming button. What gives?


Please check in the box which held your Black Berkey purification elements. The box should contain two (2) elements. Attached to each element should be a rubber washer and a wing nut. Also in the boxes should be what could looks like another single black rubber washer. This is your priming button. It is thicker than the washer and the center hole is smaller. This black priming button can easily be confused with a washer; so we asked the manufacturer to change the color of the priming button back to tan.



I just purchased a Berkey Water Filter but the system is hardly filtering any water at all. Am I doing something wrong?


Typically the problem you are experiencing is due to high water tension, which prevents the air from being purged from the micro pores of the new purification elements. Water tension is higher in certain parts of the country and can change from season to season. The higher the water tension, the more difficult it is for the water, using gravity pressure, to force the air from the micro-pores of a new element. Included with your Black Berkey elements is a priming button and instructions for use. Please remove and prime your purification elements, re-install them and that should fix the problem.



How do I know when it is time to replace the elements in my Berkey water filter?


The best way to gauge when to replace the filters is to do the following:

  1. Multiply the number of filters in your system by 3,000 gallons to get Total Gallons For All Filters within the system.
  2. Next keep a track of how many times you need to refill the upper chamber in one week.
  3. Then multiply that figure times the capacity in gallons of your particular system (for example the Berkey Light™ is 2.75 gallons) to determine Total Gallons Used Per Week.
  4. Finally divide the Total Gallons Used Per Week into the Total Gallons For All Filters and that will tell you how many weeks before the filters should be replaced.
  5. 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.

By the way, if you have been using your filter for some time now, you can still use the above formula to determine when to replace the elements. Just count forward from the date you purchased your Berkey filter.