I used it. I saw pluses and minuses.
Pluses:
-Seemed to help eliminate my hair/byropsis algae issues (clearly came back after stopping)
-Seemed to help one particular colony open up more (clearly got worse after stopping)
Minuses:
-Created a slime coat all over everything, which then made its way into my skimmer and sump. This stuff was really slick and gooey! (Went away after stopping)
-Clouded tank (Went away after stopping)
I was dosing less the the recommended amount before I stopped. I am not dosing even less on a less regular basis to see if I can get some of the benefits without the slime/cloudy issues. It really does seem like people have vastly different results on their tanks, at least from a "problems" side of things. I have been using Ca-VitC powder.