Couple Questions, One on Exhaust and One on Co2

Hey guys

So im converting my bathroom to an indoor garden and here is my setup. The area will be 5x5 with reflective siding

1000w HPS
424 cfm 6 in fan
6" air cool hood (easycool6)
6in carbon filter


so.. i have the fan and ducting, i was going to remove the bathroom exhaust fan and run ducting up where the cieling fan was previously. i dont forsee this being an issue, but wanted to get opinions. i looked and duct inside the vent housing is only about 3 inches... also hanging the fan i am open to suggestion.

I will be using the ac vent for intake, and hoping that should be sufficient with the negative pressure from fan.

I just found a 20lb co2 tank from my old kegerator.. what type of regulator should i use if i am wanting to go low budget? should i just open tank for a few seconds every day at lights out? (when fan off)

going to start construction this weekend, will post progressive pics.

if u just vent into a hot attic that is hotter then growroom it can lead to condensation and possible mold

CO2 need to be added when the lights are on. the plants dont use it at night.

So I would need to run my ducting for light separate from carbon filter if I'm running co2? I was going to run the exhaust pulling air through filter then hood. I tried to find some guides but couldn't find one relative to my design. Pics soon I promise. Need to pull vanity out

you need to use your window as a intake for your light air, so outside > light>fan>attic/exhaust. then run your co2 when the lightis on. hydro farm makes a cheap ass regulator there only like 95 bucks. and I'd guess that you need to run it as slow as possible for a few times each cycle