Update: I was able to get a cleaning cap delivered overnight from Amazon. I followed the instructions in the user guide for the IC40. There was very little scaling visible by looking with a flashlight. I used a diluted acid wash (4 parts water, 1 part acid) and only left the mix in there for maybe a minute (very little bubbling) and then rinsed well. After the cleaning the IC40 is now showing a level of 2,950 (increase of 300ppm) and the salt level light is now green! It's still reading lower than our test so I guess the calibration is the next step but I wonder if it's possible our K-1766 kit is bad. I want to be confident in our test results before doing a calibration but at least it's back to a 'good' salt level and we are producing the chlorine we want. Thanks as always for all the help!