My local reef shop sells premixed saltwater made with Fritz. He swears by it. I hear its 10dKH and 450Ca. Im running an LPS and Softies only tank. Been running IO since the beginning and I keep my dKh around 9 and Ca hovering around 400. So far the system is cruising, corals and fish thriving. But he sells premixed Fritz saltwater for 80 cents a gallon -made with high quality RO/DI water. Thats less than I can buy a gallon of distilled water from the store. -very compelling.