No gas? Temps should be in the 70-75F range.
Gas = up to 85F, maybe a little more.
The use of LED's require
NO temp increase! 70F is the target.....
Im not an led fan so I'm not a good person to give advise on them. I run 1000w double ended hps and have my temps around 80. I use a co2 burner and keep my ppms 800 in veg and 1200 in flower.
Gassing in veg is not worth the time or money as it makes almost no difference.
2k watts in that small a foot print? I hope your running Sativa's.....You can run your ppms at the max of 1500.
Some time ago I wrote in a posting the rule for figuring lighting in watts vs rise in Co2 levels.....I don't even remember where to look for that right now.........blah, just spent 30min looking for it......don't feel like typing that much....
Think of it like this.....The more light you use,,,the more gas you should use as it allows the plant to actually use the light effectively....You would be surprised at how a plant changes at the cellular level throughout the day (to actually protect it's self from the light) and back again at night..
Doc