You will get some very mixed reviews on bio-pellets. I have been using them for close to a year and had good success.Good growth, decent colors, no rtn or stn. Others have had problems with rtn, poor color, bacterial blooms, etc..The thing with bio-pellets, imo, is you have to watch the corals closely for signs of fading, bleaching or color loss. Bio-pellets, once they kick in will strip the water to well and the corals will suffer. Just feed the fish heavy after nitrates and phosphates are reduced to near 0. If you have high nutients before starting, reduce the amount of bio-pellets that is recommended or you will most likely get a bacterial bloom. When I first started using them, I had a bout of cyano, but started up the gfo reactor and the cyano disappeared. This is my experience using them.