I have been using it about four months with good growth. I started with about 25 mls twice a day in a 29 gallon biocube(actually 21)gallons. I'm up to 100 mls twice a day. This is a tank started in January, with no real corals added for a about 6 weeks and very slow additions of new coral. Water changes were plenty for the first two months. It keeps the alk, pH, and Ca++ high. I like adding a specific amount per day, since my evaopration rates vary wildly.Have you been using it long?