OneStopReef

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.

with a small tank like yours and the current livestock u have, its best if you keep an eye on the water parameters. The feeding and pooping will surely fluctuate your water parameters quickly. Don't over feed. just my two cents worth Also, how is your mandarinfish doing? has it been eating? mandarinfish requires a bigger tank coz they need to graze on liverocks for pods that it feeds on. And pods will be eaten much quicker than the colony can reproduce in a small tank with limited liverocks...which... will deplete the food source for the mandarinfish soon... try encouraging it to eat if it has not been eating. cheers!

Ahh okok THe microbubble coming back out from skimmer?might still be breaking in period? Or maybe can try putting a sponge at the outlet?

Fishes added already? Or just planning?

Neat tank

Algae Scrubber is the a good natural way to deal with nuisance algae or phosphate. (For scrubbers built in the sump itself) Just be sure to construct one that is only able to grow algae on the scrubber itself, not on the sump tank glass and floor. Coz if that happens.... then weekly cleaning will be a chore when you scrub them off... they will float in your water and you will have another problem. Another way would be Rowaphos. Nice tank btw!