Beginner's Apt. Grow Room

First off, understand that I'm learning as I go along and while my knowledge is very limited at the moment, I hope to be well prepared in a couple of weeks.

The space: Roughly 7 feet long by 6 feet wide and 8 feet high. It is a walk-in closet that is attached to my bedroom's bathroom.

What I have: A 400 watt HPS light in 8" cool tube with MH conversion bulb and 10 super skunk seeds plus 5 free ones.

What I think I need: An exhaust line with an 8' inline fan plus a DIY carbon filter. Also, a ph meter and a thermometer because of my lack of experience.

Now I figure that once I'm able to differentiate between male and female plants, I'll be left with around 6-8 females, so my space and light should be fine. But do I need a grow tent? The closet does butt up against both the apartment hallway and another apartment, but shouldn't the walls naturally contain any lingering smell or sound. As to inside my apartment, the closet has an open doorway to my bathroom so I feel like it can freely air out and exhaust, with the only drawback being that I have to keep my friends away from my place.

Anyone with experience, please point out any holes in my gameplan that you see or costly elements that I may have overlooked as I am sure that there are many.

Personally, I think you have an awesome space. I would think the walls would contain the smell and noise. I have never had any problems but the untrained noise can smell wonders. If you wanted a tent or something like it, there are some pretty big cabinents that would be perfect if you had a cool tube like you said. Put some intake, exhaust and a carbon filter and I would say you would be good to go. Ill be watching. Here is a link to my grow

https://www.rollitup.org/grow-journals/234597-wonders-medical-grow-purple-widow.html

as long as you have a inline running with a filter and the humidity is not higher than 80 percent yull be fine. just turn your fan on when you get it and walk out in the hall and listen for w/e sound it might give off. Also a ph meter and a thermometer are good for any grower to have experianced or not. Have you checked how many ppm the water that your useing has?

welcome to RIU..u NEED a PH and PPM meter for sure,or else ur just wasteing ur time and money, i think ur going to need a bit more light (how much u trying to grow?)..keep in mind a 400watt covers a 2x2 area for flowering, u should grow out ur 10 seeds (useing the 400watt) and pick the best female and use it to take clones..then go from there, good luck meangreen