The multi-detector optical configuration assures long-term stability and minimizes stray light and color interference. The new ratio metric design allows for easy and accurate testing. The nephelometric mode measures 0-40 NTU/FNU, ratio metric mode 40-1000 NTRU/FNRU and 1000-2000 AU. Now pinpoint the range of interest with better, more reliable results. Ideally suited for low-level drinking water applications, mid-range industrial applications, and high-range environmental applications.