* How to determine a cartridge life: “PPM/Gallons life” is the calculation of a compound in the water measured in Parts Per Million (PPM) and that number of PPM is then divided into the rated cartridge life to determine the approximate life of the cartridge when used on a water supply with that level of contaminate in the water. FOR EXAMPLE: A cartridge with a rated life of 7500 PPM/Gallons for sodium reduction is placed on feed water which contains a level of 24 PPM of Sodium (Na). The PPM life of the cartridge (7500) is then divided by the actual amount of ppm (in this case 24) which give that cartridge an effective life of 312.5 gallons for sodium reduction when the water contains 24ppm of Na. |