Even water that looks perfectly clear can have low UV transmittance (UVT). UVT is a measure of the percentage of ultraviolet light (at wavelength of 254 nm) that passes through the water, which indicates the water quality for receiving an effective UV dose for disinfection.
Every UV Pure unit is designed to alarm when its sensors detect UVT below the set minimum level, typically either 50 or 75% UVT depending on the water application (for example, potable or reuse water). If the UVT drops below the unit setpoint, the system will alarm.
If the unit indicates a water quality alarm, check that the sensors, quartz sleeve and reflectors in the unit are in good working order (refer to your Instruction Manual). If the alarm continues, test the water quality for UVT to confirm if it meets the unit setpoint. If the measured UVT is below the setpoint, you may need to upgrade your water pre-treatment equipment or UV Pure disinfection system.