My 29 gallon (which was stocked about a month ago) has a bit of a funk to it. All my water parameters are normal and its not overstocked (4 Red Wags and some ghost shrimp - no plants.) I'm running a HOB. The smell isn't fishy just a little funky and I only notice it when I'm at the tank or above it such as on the stairs nearby. Is it normal to have a bit of an odor? What can I do to help bring it down?