Hi btownbudda,

As killerweed420 pointed out co2 allows you to be able to run higher temps but it is not necessary to run higher temps to see the benifits of it. Plus while 1500 ppm is nice level for higher temps like 90 or so, at 75-80 you get the same increase in growth rate with a lower amount, maybe 800-1000 ppm.

Here's a source for a couple of CO2 meters, the least expensive I've seen. I have and use the TIM-8 in my personal grow. And the PC-board one to interface to a computer holds much promise in setting up your own control system. CO2 Meter | Indoor Air Quality Products - Welcome Just saw the one on sale for $129.95, does alot for the money!