250 g cylindrical sticks of 100% trichloro-s-triazinetrione magnum type to control algae and bacteria in swimming pool water. Ideal for long-term feeding in the skimmer, some automatic chlorinators and floats in smaller volumes of water. They also act as chlorine boosters / stabilizers for salt-treated pools. Recommended as Stage 3 of the Pure Wow Program in order to obtain guaranteed results without algae.