Osmonics' Well Sanitizer comes in the form of dry chlorination pellets for the temporary sanitation of wells, storage tanks and cisterns. The pellets sanitize well water from top to bottom, dissolving as they sink and offering 70 percent concentration. They are sized for easy handling and are designed to pass through small restrictions in the well. Well Sanitizer comes in a 4-pound, DOT-approved container. Osmonics, Card No. 187