Today I walked into my room and the smell hit me. Is smells like rotting food or compost. And the problem is I don't have very good air flow in my room so my room will smell like this for about a week no mater how much aresol spray I use. I decided to find out which tank it was coming from. ( I have 2 tanks in my room a 1 gallon and a 10 gallon). It was coming from the ten gallon. I just did a 80% water change. How could the water already smell bad? It has a filter. Is the filter bad? Please help me.