Well guys I have been planning to do this for oh say 2 years and now finally am going to do it. I am pretty noob with all this and would appreciate any tips and suggestions. I'm going to be updating this as much as I can and am probably going to buy a decent cam this weekend.
Here is what I got:
1 closet 42"W x 8'H x 45"D
The room is actually 12' tall but that would be nuts so I decided to put in a new ceiling at 8'. I had to remove the old drop down ceiling cause it was pretty old and these old houses have a tendency to drop old plaster dust through any cracks you have in your ceiling. To solve that I am going to just put up some plywood and trim/caulk that.
Under the new 8' ceiling I am gonna mount my 6" inline fan (about 440cfm) to the highest back corner, somehow. I don't have a carbon filter anymore but I do plan on making my own this time and it will hang from the ceiling somewhere.
I do have a question about the best way to sequence the whole ventilation system. I plan on only having only one inline fan, a home-made cool tube, and a home-made filter.
Should I have the fan like so:
Exhaust Hole >> Inline Fan >> Filter >> Cool-tube
or
Exhaust Hole >> Filter >> Inline Fan >> Cool-tube
or does it even matter?
Does intake size really matter? If so do you think 6" intake is large enough for this closet?
Other equipment I have is:
Mylar & plastic sheeting
400watt hps/mh light
42watt fluorescent bulb (is that good enough for cloning/veg?)
home-made DWC systems with pure blend pro nutes
White rhino nirvana seeds
Basically I have everything I need but meters and a carbon filter.
Do I need to check ph and ec or do i also need to check tds? Can you guys PLEASE recommend me a good reliable meter. I had a control wizard but it broke. I'm thinking something under $150.
The water in this town is heavily nitrated. What do you guys do to prepare your faucet water? I suppose i can go buy some jugs from the store but if there is a better way let me know!
Well I'm out for the night, thanks for the help!

*I messed up on the gfx, The fan is going under the new ceiling not on top
I will list more later and take pics very soon.