I use parts a&b, corals seem to like it. It helps keep my nitrates up so it's doing it's job haha. I tend to dose right after lights out so corals are usually already in feed mode
I tried it for a while. It’s good stuff but I believe it works in conjunction better with their NoPoX. If using it separately, use it sparingly at first. It will raise your No3 and Po4 fast.