I think Ive already mentioned how i do CO2 santa cruz but Ill recap it here again and just add to what Bluebear said.

The simplest method I have found is for a bottle, regulated, with an environmental controller and ppm meter that controls the exhaust, CO2, and lights. I run the CO2 to fall from the ceiling just from tubes. Then I have multiple oscillating fans on the floor that are aimed up. This picks the heavier-then-air CO2 off the floor and distributes it around. You really dont even need to drip it from the ceiling with fans, they do a good job of getting it around.

I run them on a 45 mins-60 minutes on, and then a 15-20 minute exhaust. Obviously this is not a set in stone number because if you have a heat issue then you might want to run 45 minutes on and 30 minutes exhaust, etc. Obviously when the CO2 is released, your ventillation stops, and the temperature will rise. The idea is to find the perfect amount of CO2 release time that allows you to raise the temp but not exceed it for to long.

This is where sealed lights really come into play because they can keep temps down much easier. However in some odd situations where cold temps are present, you can turn off your sealed lights to heat up the room faster. Also remember you must have atleast 600watt HPS lights (but 1000 watt or 600 digitals are better) and like Bluebear said, atleast 85 F. I like 90F if I can keep it from going over 90.

I am a fan of running the ppm at the same ppm of your nutes. this makes sense in many ways and is also the way I was taught so I am partial to it. I do not use CO2 in veg at all since I have never personally seen enough benefits for the cost/annoyance. However we have always started CO2 almost immediatly after starting 12/12. PPM meters are very important because you can never do 100% math with predictions. I have friends who are to cheap to buy a meter and they still get some very good increases in yield from the CO2, but it took them more then a few messed up harvests to learn their method. If you are going to predict, then make sure you error on the light side. I would never go above 2000. The max my nutes get is about 1800-1850 so thats the highest the ppm gets.

Finally...never any CO2 during lights off. You want to make sure all CO2 is exhausted out and you have nice fresh air available. You can do this easily with a timer if your just using a regulator, or almost all high end environment controllers come with photocell sensors.
Racerx Reviewed by Racerx on . All Questions Concerning CO2~ So i am setting up Tanked co2 in my grow area this weekend and need some advice. i have been getting completely different answers from different people about the methods of co2 usage. as many people have questions about co2 on this forum, i thought one thread for co2 questions would be usefull as it would give more info in one place. So if you have any questions about co2 or you can help some one with co2 questions, please ask or do so here. it will make it easier for every one! I found some Rating: 5