What is CLR?
Corrected Lactometer Reading — what the float in the glass tube tells you, adjusted for temperature.
A lactometer is a float in a glass tube. It sits higher in milk that has more solids and lower in milk that has been watered. The number is read off the stem and corrected for the milk's temperature, which is where the C in CLR comes from. Normal milk reads roughly between 26 and 30.
Many dairies own a lactometer but not an SNF meter, because a lactometer costs a fraction as much and needs no power. So they price on CLR.
Dairywala converts it with SNF = CLR ÷ 4 + 0.14 + fat × 0.2, then runs whichever formula the member is on. The 0.14 is adjustable in settings, because societies differ on the constant they use.
You can also keep a rate chart with CLR across the top instead of SNF. Then no conversion happens at all — the cell is read directly.