Micromet is a slowly soluble food-grade polyphosphate that keeps scale-forming minerals in solution and prevents formation of scale on the freezing surface of ice machines. There are two types of Micromet that may be used: Micromet crystals which dissolve at the rate of 25% per month and require monthly recharging, or 6R Micromet which dissolves about 3-5% per month and lasts up to 6 months. Both are NSF listed and are U.S.D.A. accepted.