Do you think that's really necessary for a device on which the sensors use capacitance to read through the tank wall, only draws milliamps, and only reports 1/4, 1/2, 3/4 and FULL?
As for SCAD'S advice not to use fresh water, they should have advised against using DISTILLED or filtered water, 'cuz every liquid has a dialectic value. Pure distilled water with no impurities has a value of 0 so the sensors can't read it.
Btw, "SOLO" isn't a brand name...it's just the name for the single tank version of the SCAD/Profile gauges. They also offer systems that can read up to 8 tanks.