HI Randy, Two questions,1. (magnesium sulfate heptahydrate (3 cups) 1cups=?grams 2. I saw that the BRS formula is the same as yours But can I use AF REEF MINERAL SALT instead of Tropic Marin's Part C??? If applicable, how much solution do I need to use? I plan to mix with AF concentration (25g 1000mL RO/DI) and use KH solution twice.