then spend 200-300 on a monitor/controller and your back at $500.
co2 is great IF you use it right. you have to have your room tight, your exhaust and enrichment synchronized, and your temps in constant check or IT IS A WASTE OF MONEY.
Why not use the CO2 calculator to determine your needed CO2 output? All you are doing is trying to find the most expensive way to go about things... All you need is 2 timers... One for CO2, one for exhaust... I set mine to run every 15 minutes, or once an hour for 15 minutes(depends on which tent/room)...The CO2 calculator tells me everything I need to know...
Hell, if you are going to buy a controller, you might as well buy one for all the light, pumps, everything...Now, CO2 is going to run you $1000 or more... Atleast, that is your logic, right?
But go ahead and keep explaining to the guy who has a $500 CO2 setup for $150, with excellent results...