The EZ SDI from Aztec, N.M.-based RODI Systems Corp. automatically monitors the silt density index of reverse osmosis feed water following ASTM 4189-95. RO operators can now quickly and easily check the effectiveness of RO pretreatment equipment. Use of the EZ SDI can prevent RO fouling before it leads to downtime and expensive membrane cleaning. The EZ SDI is available in both single-test and four-test versions.