1st grow in 30 yrs

My 7 yr old Blue Cheese seed that was gifted to me has not been drinking as much as the others. I only had one old seed (1 popped out of 30 seeds I was given) and the rest are newly purchased. I have tried to keep them tied down to about 12 inches each. Split the stalk on two but did not seem to negatively affect them. In fact, those two are drinking to most water. Didn't do too well with developing my canopy. Honestly, I spent minimum amount of time in the room with them. 30lb Co2 take last about 10 days at 700-800 ppm. I have a 12ft x 8ft room and only using have of it at the moment. Thinking of building make shift, short wall around the tray to see if I can trap some of it for a longer period.