How to Do the Berkey Water Filter Red Dye Food Coloring Test

 The Black Berkey  Filter Purification elements are powerful enough to remove red food coloring from water. Performing a red food coloring test on your Black Berkey Filters allows you to ensure that your system operates properly.

How to Do the Berkey Water Filter Red Dye Food Coloring Test

  • We recommend this test be done upon first use and then every three to six months to ensure the Black Berkey Filter Purification elements are working properly.
  • The red food coloring test is only designed for the Black Berkey Filter Purification elements and NOT for the ceramic or other filter elements that do not filter out food color. This test is also NOT recommended for the Sport Berkey water bottle.
  • Please make sure the food coloring is RED. Red food coloring (unlike the other colors) doesn’t have any minerals, so the element recognizes it as a contaminant.
  • The red food coloring test should be done after priming your Black Berkey Filter elements.
  • How to Do the Berkey Water Filter Red Dye Food Coloring Test
How to Perform a Red Color Test on Berkey 
  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 before performing a red food coloring test 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 filter elements installed) on similar-sized cups directly underneath each Black Berkey Filter 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 a teaspoon of red food coloring for every gallon of water.
  4. Allow the water to run through to the bottom chamber.
  5. If the red food coloring 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 defective or exhausted.


  1. Are the wingnuts 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 wingnuts are on too tight, this could cause stripping on the stem's threads, preventing a correct seal.
  2. Are you using actual “red food coloring” or another color or type of color? Red food coloring is the only type recommended for this test.
  3. Is the washer for the stem inside the upper chamber, and is the wing nut secured at the bottom? If the washer is outside 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.
  4. 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.
  5. 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. Now you are ready to repeat the test.

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