The particles that pass through RO layer and enters the permeate are referred as the salt passage. The components that don't pass through RO membrane are rejected salts. Here is a salt passage formula to calculate the salt passage percentage. As per the Salt passage reverse osmosis formula, to compute the percentage, divide the total dissolved solids product by the total dissolved solids feed, and multiply the resultant value with 100 to know the passage percent.
The inverse of salt rejection describes the salt passage. Both the salt passage and salt rejection describes the same phenomenon in the Reverse Osmosis process. Use this Salt passage formula to determine the passage percentage on your own.