How to tell salt dose on WaterRight IM-1054

[SoftenMe]

Bought a house, it has a WaterRight IM-1054. I'd like to figure out how to tell the salt dosing on it. We're using just about exactly 1/3 the water of the previous owners, so now I have it regenerating 1/3 as often and if it's at 15lb that is somewhere between spot on and moderately excessive regeneration based on water testing and the ensuing calculations. However, I'd like to be able to confirm the dose so I can be sure it's set up right. Does anyone know how salt dose is set on these things and how to check it? Thanks in advance!