There are 4 names in this directory beginning with the letter R.
Chemical testing compounds that are used to test for Chlorine, Bromine, pH, Total Alkalinity, Calcium Hardness, etc.
The amount of measurable bromine remaining after treating the water with bromine. The amount of bromine left in the pool or spa water after the bromine demand has been satisfied.
See Free Available Chlorine (FAC).
The point at which the water returns to the pool after having traveled through the filter.