The cal/mag from Botanicare uses nitrates, so you get some nitrogen with it. The Botanicare product gives the same results as epsom salts, but it's not the same. However, the CaMg+ product from General Organics is calcium carbonate and magnesium carbonate...otherwise known as epsom salt and common chalk. The General Organics product suspends the epsom salt (1%) and chalk (5%) in a handy molasses/sugar water solution.