red sea's reef foundation system

Hi, I have a 80 gal mixed reef tank, 25 gal sump, ATO. Currently at 8.6, 422, 1230. Having a hard time getting the Mg levels to 1400. Using Red Sea's Reef Foundation system (liquid). Looki g for recommendation of using Red Sea's Reef Foundation system vs Kalkwasser? I read Kalk is a great...