Well the easy way is to use a controller. You set your PPM and then set the exhaust cycle the controller does the rest.

For me I like 1800-PPM total, room air is about 300-ppm so I add 1500-PPM to reach the 1800 number. You can use timers you just need a few of them.

I run the CO² generator 10 min to reach the 1800-ppm every hour and 1/2. I remove the air about 10 min before I turn the CO² back on and start all over again. For me I vent differently then most do. I use 2 motorized dampers so my carbon scrubber can put the scrubbed air back into the room or exhaust it out of the room. Depending on the cycle it's set for.

Example:
8:00 am lights on CO² running.
9:30 am switch the dampers from returning the scrubbed air back into the room to vent to the outside.
9:40 switch the dampers back so the air returns back to the room.
9:41 turn CO² generator on
9:51 turn CO² generator off
11:21 exhaust again and start all over.

The AC deals with the heat so I don't have problems with heat build up. Fans move the CO² around and the idea is to fill the whole room not just one area. The plants take what they want. You can rise the level above 2500-PPM for a day or so if you have bug problems too. CO² makes a good insect killer, the plants will use up what they want so don't worry about over dosing them on CO². You do need to play with your timer settings and know your plants and room.


http://www.hydroponics.net/learn/co2_calculator.asp

This calculator may be helpful to you.
Zandor Reviewed by Zandor on . Zandor?What is your CO2 regiment? How do you administer?What do you do about exaust when the CO2 is running(how long do you keep your exaust off after CO2 ijection...Please let me know how to use CO2 and still have good enough ventalation.I want to get a fat CO2 yield but I don't know how to go about it with exaust in such a hot climate. Thanks Zandor,J-Dog Rating: 5