poolife® Exclusive Pool Care Collection NST™ is an alternative to 3" tablets and does not contain cyanuric acid. Perfect for use in a skimmer, this product will destroy bacteria and organic contaminants without over-stabilizing your pool water or adding additional cyanuric acid to your water. Each long-lasting tablet will continuously sanitize your pool in the skimmer for up to one week! This product is an innovative, patented technology that provides long-lasting, slow-dissolving chlorination. It’s compatible for use with pools equipped with salt chlorine generators to help maintain the proper sanitization level.