PPM is the abbreviation of PARTS PER MILLION. In the additive formulation industry it represents the minuscule amount of chemical components included in a formulation. The treat ratio determines how much 'room' is available in a formulation to include PPM's of active chemistry.
To convert the additive ‘treat rate’ into PPM (parts per million) the first number of the ‘treat rate’ is divided by the second number and the result is multiplied by 1,000,000.
Example 1: IF, an additive ‘treat rate’ is 1 to 7,500 (1:7500)
then, 1 is divided by 7,500 = 0.000133 x 1,000,000 = 133 PPMs of active chemistry
Example 2: IF, an additive ‘treat rate’ is 1 to 1,500 (1:1500)
then, 1 is divided by 1,500 = 0.000667 x 1,000,000 = 667 PPMs of active chemistry
Example 3: IF, an additive ‘treat rate’ is 1 to 500 (1:500)
then, 1 is divided by 1,500 = 0.002000 x 1,000,000 = 2000 PPMs of active chemistry
PPM calculations remain true regardless of the size of the container as long as the liquid measurement remains the same (i.e. gallons to gallons, quarts to quarts, pints to pints.) The results in PPMs are the same regardless of the size of the container.