I have a 240gal tank with 4 10-12in silver aros 1 16-18im jardini 1 tiger oscar and 1 catfish. Yesterday i did a water change and i use api stresscoat and stress zyme +. I tested my water today it was at 6.2-6.6 ph and tested med high in amonia no2 and no3. What could be the cause and what can i do . Water temperature is at 80-83. Just added another heater to keep it at a calm range since the tank is in the garage