Is the brand we use, but not sure if that is the same model. We also added a monthly requirement to check the actual conductivity vs the controller value and then zero out the sensor as well. We had one that was taking care of 3 towers and we think it was out of cal for about 3 months, but the it was reading just above the low alarm value, but the actual value was 6000 us! Let's just say we were too reliant on the sensor reading correctly.
Even with redundant sensors and alarms a once monthly check is risky. A tower and its associated chillers can become fouled in a matter of days if the bleed stops.
That's if you have chillers. Also that's why we tied in the BMS input for alarming/monitoring purposes w/trends.
The biggest issue I found is once it was tied into the BMS the guys seemed to think it would alarm when there was a problem, and forgot about other parts of the system that weren't tied in yet. It does alarm if it can see it but it doesn't take place of regular maintenance.
BTW - the once a month is a forced/documented re-cal of the sensor and zeroing it out. Towers are 'supposed' to have a basic inspection weekly.