The BOQU CODS-3000 online COD Meter use UV principle COD Sensor,the UV COD Sensor is based on the absorption of ultraviolet light by organic matter, and uses the 254 nm spectral absorption coefficient SAC254 to reflect the important measurement parameters of soluble organic matter content in water, and can be converted into COD value under certain conditions. This method allows for continuous monitoring without the need for any reagents.