“Master Clear Chlorine Granules is a Di-chlor chlorine sanitizer in powder form for quick-dissolving sanitizing of your spa’s water. In this form, the chlorine is more pH neutral to keep from throwing of the pH & alkalinity balance of your spa’s water. It is also one of the best sanitizers for treating higher temperature environments. Di-chlor chlorine is the best type of chlorine to use with the Eco-Pur Mineral Purification filter system, & will keep your spa looking & smelling great, as it cleans & purifies your spa water, keeping it clear from bacteria & other contaminants. Use daily or as a weekly shock treatment.