The easiest way to get CO2 to the plants is to get a co2 setup. You can get them on ebay for like $140. Make sure you get one with a flow meter, solenoid, and regulator, not just one part of it or one with a bubble counter. They are for fish tanks, not plants. THen you need to either rent or buy a co2 tank from a welding supply store. You will need some timers to run the CO2 solenoid and your fans, a digital one to run the CO2 part, and use a CO2 calculator online to figure out how long to have it on.
ANd to Cra8z, the 24hrs is not needed so to speak, but it does help to speed up flowering. When you throw them under 12/12, they will take about a week or so to start to bud. With 24hrs of darkness they will start to bud a little quicker. After the plants have gotten 12hrs of dark, they begin to produce the chemical that makes them flower. Having the lights off for 24hrs will allow them to build up an abundance of this chemical and thus speed up the start of flower.
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