question about co2 and temps

i justed started injecting c02 into the room, im using a sentinal regulator and a timer with a AIR-4 photosensor climate controller, im having the timer inject 9 min at 15cfh every 3 hours during the light hours with a 3 minute recharge 1.5 hours after each initial fill up,( the greenhouse is 12x12x8( they reccomend a 5.5 minute burst every 3 hours, according to my room size, i dont care if i overshoot right now, better safe then sorry in my opinion) right now i have no money to buy a nice c02 meter, i just have the hydrofarm syringe type co2 tester, i tested them right before the lights shutoff this morning and the levels lookied to be aroun 500-600, the temp got up 82, my question is this safe for my plants, they look okay and healthy, no curllying of leaves, but i was always afraid of temps going over 80, co2 is something new to me, but ive heard its the single one thing that will double your yeild.
please, any advice would be helpful,
thanks
kyle

Just started it myself.Don't hang out in there without shutting co2 off.I did got a little of air like k2.Bad ass headache other than that.On a timer it's best to shut intake and exaust 1/2 hr every hr lights are on.Spurting 15 min on a low under 2 flow every hr lights on.Be sure and leave circulation fans on always.I have read it's best to have a fan on ground blowing strait up do to co2 being heavier than air.Hope this helps some.Oregon024