if anyone can nail the 70 gal, it's you G.
what centers are you going with, what strain, what height are you flipping at, what's your ceiling height?
Centers are at 52.5"
Strain: Hash plant (sensi seed bank) and Norther Lights #1 (sensi seed bank)
Flip at the usual 24" high
ceiling is 7'6" from floor and just over 4'3" from the top of the buckets
what are your plans for nutes and water temp?
Nutes are the same Advanced Pack I have been on in the past:
Sensi Grow/Bloom A&B
the respective AN bloom booster depending on week of flower.
PH DOWN FROM AN!!! set ph at 5.58 at the beginning of the week and forget about it till the flush
Chiller set at 62* keeps buckets at 65*
i hear you on the co2 exhaust. i just switched out a pilot light gen for a bottle. i've found that when you seriously seal up a room this size the pilot light alone can get you above 5,000ppm at times.
My pilot light keeps my room at 2100ppm if I don't exhaust at night