I have used rinse aid mixed with fairy as a trad solution for years, did a post on here about it. I love the stuff, plenty of slide without all the suds. This is a great cleaning solution, when used with all in one single pass tools like the Wagtail or backflip.
Wouldn't want to chance putting it in my WFP system though.
Just try putting it into a bucket of pure water, and then check the TDS reading. If is still o ppm, then it could be used. Dai