Purple up isn't useless but there are plenty of better (and cheaper) alternatives out there. Kalkwasser will do the same thing, much (!!!) better, and for a fraction of the cost. Coraline is, like most algae, not picky...CA, Alk, lights and off you go.
Kalk also does not contain mystery trace elements that you have no idea what they do in the long term. Most likely harmless and useless but why pay extra for it when you can get a years supply of Kalk for a few bucks.