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Rosemount™ 499ACL Free Chlorine Sensor
rosemount 499acl sensor
The 499ACL is a family of membrane covered amperometric sensors used for measuring free chlorine, total chlorine, and monochloramine.
The Free Chlorine Sensor, 499ACL-01, does not require sample pre-treatment or expensive reagents to maintain. The Total Chlorine Sensor, 499ACL-02, eliminates the need for pH correction with a standard reagent sampling system. The Monochloramine sensor, 499ACL-03 does not use reagents or sample pre-treatment for measurement. All three sensors have an easily replaceable membrane that does not require special tools.
Rosemount™ 499ACL Free Chlorine Sensor


1 lb/3 lb (0.5 kg/1.5 kg)
Measurement Range
0 to 10 ppm (mg/L) as Cl2. For higher ranges, consult the factory


  • Measure free chlorine without sample pretreatment
  • No messy and expensive reagents needed
  • Automatic correction to at least pH 9.5
  • Easily replaceable membrane; no special tools required
  • Automatic compensation for changes in membrane permeability with temperature
  • Automatic pressure equalization maintains correct membrane tension
  • Variopol connector option allows the sensor to be replaced without running new cable