I started using it a week ago.
I had a mayor hair algae problem on my sand and rock. It has almost completely disappeared...
I have never had any significant coraline growth. I have found coraline spots on my glass for the first time ever in about 7 or 8 months!!
I believe this stuff works, also made my water crystal clear.
I completely recommend this stuff after only 1 week a saw a huge improvement and my water parameters are right where I want them to be.