Yes, just add this code to the Advanced tab of
both DOS heads:
If NSW_Lo OPEN Then OFF
(assuming the name of the optical sensor is NSW_Lo)
You could also set up an alarm notification so you know when it's time to mix new salt water. I use a virtual output as a timer so the alarm is only sent once, then disabled until you refill the tank. This prevents it from nagging you every hour, and from blocking any more important alarms from coming through:
[Mix_New_Salt}
Set OFF
If NSW_Lo OPEN Then ON
When On > 005:00 Then OFF
[EmailAlm]
Set OFF
If Output Mix_New_Salt = ON Then ON
See my Apex tutorials for more tips:
https://www.reef2reef.com/ams/authors/suncrestreef.93940/