me, I wouldn't worry about it. Your business is your business. You could have a grow tent in the middle of your bedroom. If they saw and asked what is was, or more specifically what was in it. It doesn't fucking matter. It's none of their business. You really don't have to explain it any further than that. It could be vegetables, it could be marijuana, it could be a meth lab. that's for them to speculate, and for you to not give a fuck.
Of course in the effort of avoiding an unnecessary situation like that, keep something locked with your own lock like someone else mentioned. How many units in your bulding? I doubt maintenance changes some filter every month in every unit...? really.