i used it and it didnt affect any parameters. Just make sure you use an air stone to oxygenate the water and do the 20% water change after two days. It worked wonders by the way, i had a cyano outbreak and tried everything in the book to get rid of it before going chemical, but it worked wonders and a month later still no algae and no affected params. It also didnt affect any fish, coral, or inverts.