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The easiest way to test your Berkey system, is by using artificial red food dye. Red food colouring works well in USA as it contains artificial ingredients where as some other food dyes do not. So you will need to use a specific red food colouring dye. Do not use gel based food colouring, and ensure it does not have any added sugar, glucose and thickeners. You may also purchase it from ourselves here:

Red Food Colour Link


Red Dye Test Kit

Tip to try:

Another thing you can try is blowing air through the purifiers (where the water drips out from). If you feel a lot of resistance, then this means the filter is tightly sealed to the plastic tip as it should be. But if you don't, then you will notice the air coming out from the sides of where the plastic meets the filter media. This will mean the adhesive has come loose and the purifiers will not function correctly.




The Black Berkey Purification elements are powerful enough to remove artificial red food colouring from water. Performing a red food colouring test on your Black Berkey™ Purification elements allows you to ensure that your system is operating properly.


  • We recommend this test be done upon first use, and then every three to six months to ensure the Black Berkey elements are working properly.

  • The red food colouring test is only designed for the Black Berkey™ Purification elements and NOT for the ceramic or other filter elements that do not filter out food colour. This test is also not recommended for the Sport Berkey® water bottle.

  • Please make sure the food colouring is RED. Red food colouring (unlike the other colours) doesn’t have any minerals, so the element recognizes it as contaminant.

  • The red food colouring test should be done after priming your Black Berkey™ elements.


  1. Start with an empty system (upper and lower chamber) and remove any Berkey PF-2™ Fluoride and Arsenic Reduction Filters(if installed). The Berkey PF-2™ Fluoride and Arsenic Reduction Filters must be removed prior to performing a red food colouring test in order to stay in compliance with the six month warranty on the Berkey PF-2™ Fluoride and Arsenic Reduction Filters .

  2. Place the upper chamber only (with the elements installed) on similar- sized cups directly underneath each Black Berkey element. This will help isolate which filter may be exhausted and which is still purifying effectively.

  3. Fill the upper chamber with water and add 1 teaspoon of red food colouring for every gallon of water.

  4. Allow the water to run through to the bottom chamber.

  5. If the red food colouring is removed entirely, your purification system is working properly.

  6. If the water in any of the cups is red or has a pinkish tinge, then that particular black filter is possibly defective or exhausted.


  1. Are you using the correct amount of artificial food dye? Unfortunately, a set of instructions was published that contained an incorrect measurement of red dye. The correct measurement of dye to use is one teaspoon of red dye per gallon of water. A quantity greater than one teaspoon can cause a false failure.

  2. Are the wing nuts on securely? Please do not tighten the wing nuts using any tools; they should be hand tightened to a snug fit, but not more. If the wing nuts are on too tight, this could cause stripping on the threads of the stem, preventing a correct seal. If you have inadvertently stripped the threads on your element, please contact us.

  3. Are you using actual “artificial food colouring” or another colour or type of colour? Artificial food colouring is the only type recommended for this test.

  4. Is the washer for the stem inside the upper chamber and is the wing nut secured at the bottom? If the washer is on the outside of the chamber with the wing nut, you will not have a proper seal, which will cause your system to fail the test. Place the washer on the inside of the upper chamber and re-run the test.

  5. Are the blocking plugs properly sealing the unused holes without elements? Are the plugs installed tight with a washer on each side? If the plugs are leaking, this will cause the system to fail the test. Tighten the plugs more securely and re run the test.

  6. Are you re-testing an element that you think may have failed the test? If so, rinse off and re-prime the element first. Additionally, make sure you pour any excess water out of the bottom tank. Also, if you are using the lower chamber to catch water, run clean water through the spigot to clean it out as well. Now you are ready to repeat the test.

  7. If you’ve done everything and still have a filter that fails the red food colouring test, please contact us.

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