Here's a great link for calculating CO2 by room size..
CO2 Calculator - Greentrees Hydroponics
And~ It gives you settings for your regulator to reach your desired ppm.
Well it's been about a week since my last post. Things got hairy for a minute; as I was chasing a nutrient deficiency and found spider mites instead. I removed the infected plants, (4 - which were clones from a dirty, unclean grower- I should have know better)... I cut and removed the highly...