Q: Are the StablCal or Gelex Turbidity Standards manufactured by Hach traceable to NIST ?

A: No – NIST does not carry turbidity standards, so no standards for turbidity will be NIST traceable.
However, using Formazin and StablCal as per Hach’s method 8195 is accepted by the EPA as a primary standard to be used in the calibration of turbidity instruments.
All of the raw materials used by Hach to make up the standards are NIST traceable.
For more information on turbidity measurement and calibration, follow the links above or contact us;