How much CO2 is sufficient?

3 litres of 5% vinegar 105g (3.7ounces) of baking soda mixed with 1 litter of water. This will create 1 cubic foot of co2, raising co2 roughly 1000ppm. Yeast is good too. But it's not practical for 8 weeks of flower. Buy a 15w inline fan have it sit vertically 1 inch off the floor outside your grow ambiently sucking in the very bottom of the floor. If your lucky and have more than 1 set of lungs in your home. Along with placing your tent in theeeee lowest point of the house. Co2 is heavier and will naturally sink quite dramatically to the bottom so says gravity. Anyway doing this alone with 4x lung power I keep 1000+ and can attain 15-1800 in Bursts with yeast. That's just my experience. I have 2 co2 readers in my grow.