Blue Horizons Ultimate Winter Time Algaecide is a Non copper based (Copper Free) long life algaecide with sequesterant, for the control of most types of algae, together with the prevention of staining and scale formation. Blue Horizons Ultimate Winter Time Algaecide should be applied to a Swimming Pool prior to a winter close-down. The concentrated formula treats up to 15,000 gallons and also contains a built-in scale and stain inhibitor. Compatible with Chlorine, Bromine and Biguanide treated Swimming Pools. Blue Horizons Ultimate Winter Time Algaecide is tolerant to pH range fluctuation. Winterising with longer lasting algaecide products.