Blue Horizons is a Top Quality Swimming Pool, Hot Tub and Spa water treatment branded product. Ph Plus is used to increase the PH value of the water in your pool or spa. Helps prevent or cure the problems caused by Low pH levels. The ideal pool pH levels are between 7.2-7.6. Pre-dissolve the product in a clean plastic container at a maximum rate of 100g of product per 2.2 gallons of clean warm water. Stir well. add the solution to the pool whilst the pump/s are on and preferably near to the water inlets. Also available to buy in 1kg carton.