I agree with everything you said. Cal/Mg can be added after silica IF you add silica then PH down to 6 then add cal/mg then add nutrients then PH adjust. The precipitate comes into play when cal reaches a PH above 8? I can't remember exactly.The whole idea of separation with Silica and cal/mag is that you must add them as far apart, and mix well between them. They react by creating a precipitate (cloudy looking solution)
The idea of one first and the other last is the point.....