Blue Horizons pH Minus, Sodium Bisulphate (sodium hydrogen sulphate)
All chlorine based sanitisers become less effective at killing bacteria and viruses as the pH increases (becomes more alkaline). Acid/Alkaline conditions are measured on the "pH" scale which ranges from 0 - 14. Ideal bathing conditions exist at a slightly alkaline level of 7.2 to 7.6 with Total Alkalinity of 80/140 mg/l (ppm). If pool water becomes less alkaline (above 7.6) it also gets more corrosive and less comfortable to swim in.
Blue Horizons pH Minus is used as a reducer for the pH level of your pool water when it goes above 7.6, it can also be used as a decreaser for Total Alkalinity in your pool water.