First time 80x80 Sativa

I am not sure if i wanna defoliate so early, stress factors and such. They look very healthy, i watered them 5-6 days ago with 4.5L water throughout the day and only the strawberry lemonade wanted to be watered today again, i guess she will yield me the best ones, but even the problem one after switching to flower and feeding biobloom green house feeding she started to look better and better.. i bought co2 bag and a co2 meter but im not sure if thats really doing anything lmao, maybe i will give it back it reads 400 and when im in the room it gets up to 700, i guess i cant fix that with the bag.. i though i could anyone has idea how to get more in it? the bag seems to be doing literally nothing - added new photos after lollipopping, i think i can lollipop more but i didnt wanna stress too much. do u guys think i need to lollipop more? less? defoliate? i wanna add pk1314 in day 21 - im not sure though because many people say easy for mold and shit.. anyone have experience?