Mine did nothing for a whole year, I got LED's and I kept my Mag up and my coraline has gone crazy in the past 2 months, I put some super glue epoxy JB water weld on some hydros to kill them and it even grew over that in places. IME it takes your tank time to mature, once it does the stuff takes off. That might not be the case for everyone but it was for me. Just my 2 cents