Dymax Anti-Ammonia Rock is a chemical filter material made from natural environment-friendly minerals, mainly composed of various kinds of zeolites. It can absorb ammonium ions, nitrite ions and nitrate ions rapidly for the purpose of removing poisonous ammonia, nitrite and nitrate.  It helps stablize pH value between 6.5~7.5 and removes unpleasant odours, chemicals and harmful micro-organisms in the water. Dymax Anti-Ammonia Rock helps provide the best environment for aquatic lives.