Indoor Project

So I've decided to go indoor because I believe that it will pay off well in the end but I'm sticking with soil for budget and inexperience purposes. The room is already in the works and a few things have been purchased. I'll list the materials and room setup and everything I think that'll be needed for completion. This is my first indoor experience so please feel free to express any thoughts you may have to help make it a beautiful environment.

Keeping it simple was the main idea*

Dimensions: 11x3.5x8 (entire room)

Veg Room: 4x4x8

Light: 400watt MH complete system. Includes: Radiant Hood, Lens, 15' Light Cord, AgroSun 400W MH Bulb & Powerhouse Ballast (36,000 initial lumens)

An oscillating fan is positioned to strengthen the stems and create airflow on the floor while another is pointed at the hood hole to circulate some air. It stays quite cool so I may not run duct work for this hood. The hood is hanging from chains which are then lengthened from hooks screwed to joists. The room reflects light well with mylar lining the walls. Is it beneficial to have mylar on the floor under the plants? Temps stay on average 74-81 degrees F (74-75 during dark period, 81 @ peak of light). Ballast stays in other room for safety purposes and heat issues.

Flower Room: 3.5x5x8

Light: 1000watt HPS complete. Includes: Hortilux Super HPS bulb, Hydrofarm Radiant Reflector, powerhouse ballast. along with optional active air fan cooling system (145,000 initial lumens)

Duct work will be put in place from a connecting room for intake and heat exhaust through the hood system. Mylar also lines the walls. The hood will hang as the MH by chains and hooks from the joists. The ballasts are placed in the connecting room for safety. once the duct work is complete should the active air blower be ran for the full 12 hours of light through the HPS hood or should it be controlled by a stable temperature and turned on when temps become a certain degree?

Medium: Atami B'Cuzz Coco Fiber (50l)
earthworm castings
Nutrients:
Floranova Grow
Floranova Bloom
Floralicious Plus

Containers:
solo cups
2 gal pots
5 gal buckets

Miscellaneous Items:
timer
thermostat
oscillating fans
Needed Items:
ActiveAir 180 CFM Blower
Ph pen

I've been looking to buy a ph pen but my local shop only sells one for $95. Is there anywhere I can get one cheaper? This is all the time I have for now. Suggestions are wanted, Thanks in advance. Take care

gmorning