Since we have a high concentration of feed water(Fe: 0.2 ppm, W: 30 ppm), starting after 3 weeks differential pressure was increased rapidly. so we shut down and proceeded with the CIP. After CIP procedure we found that salt rejection rate also decreased as 98% to 92% just only in a day. we just use the organic chloramine for disinfection of microorganisms and scale inhibitor based on phosphonate and polymer.