perhaps you can try doing a water change for the tank and adding in a good quality activated carbon charcoal to remove any further smell from the tank water. Another culprit might be air that is sucked into the canister. somehow, and the air gets trapped in the canister itself and is released back into the main tank. is your canister making any gurgling noise?
As for your room, for the time being until your tank water issue is resolved, maybe you can try those dehumidifiers/ moisture absorbent like "Thirsty Hippo" to absorb moisture and smell from the room?And no please don't spray any air freshener in the room... the residue will get in your tank.
Hope your tank problem gets solved soon.