Do you have enough plants?! I mean at least use Matrix as your bio-media, it is the most effecient bio-media around. It reduces ammonia, nitrite, and even nitrate. But if your going to have alot of plants you wont need it since it will cut down on nitrates ,and that is your "plant food". Plus, Discus need plants for long term survival. Did you do all your homework before you bought the Discus, and is your tank completly cycled? Add BIO-Spira, it might save your @$$...!