Added CO2 and now getting this, advice needed

Hi All, been growing for a while and had some fresh air issues so added a CO2 system.
using bio bizz all mix, grow, boom and a bit guankalong guano. growing in a weekly rotation (1 in 1 out) results before CO2 not huge but livable but as always always hunting for the bigger bud! plants that had been in for 3-4 weeks before CO2 loved and went a lot bigger, new plants are getting burnt (see pics) after a couple of weeks in and gradually worsens. had nute burn in the past and guilty of too little not too much now! all plants vegged for about 6 weeks and in at least 15-20 litres of soil.
1.2X1.2 tent
i have raised lights and dropped from 600 to 400W
vents for 15 mins every hour, CO2 released every 4 mins in measured quantity (3.5 seconds, flow rate is 17L a minute) lights on
vents constantly lights out, no CO2
temps are about 33C and humidity 60-70%
i am thinking under nuting as growth goes crazy but what? Phosphorus?
thanks for looking and any help
better pics too follow
Cheers
GG

What are you growing in (soil?) and what is your ppm? It looks like nute burn, though I'm not that experienced so it's hard to say for sure...

Whether soil or clay flush that with 1 gal distilled water then 1 day later do it again. Looks like to many nutes and salt build up. Remember plants will grow with no added nutes at all. Plants will die with to much/many nutes. It`s not the plant but the grower and over feeding is 90% of most problems also schedule used. The best HELP you can give your plant is as little as possable. Untill you know your plants inside and out all ways go with 1/4 of what you think you now and 1/2 of what is instructed. Every plant is different as far as needs and wants, even if cloned or the next generation. Called evolution!!!! Dont try to hurry to max out a grow, go slow remember exactly what you did every step. The next grow make adjustments and continuie. This is the best way for you and your buddies to only get better. Einstien say you need 100,000,000 mistakes to get 10,000 good results. So take your time, slow down and let is FLOW dont POUR it on!!! We all want massive honey dripping buds and application over time equiles possative results. Each batch gets bigger, fatter,stinky, and better with time and clean PH correct water. Spend twice as much time on growing a better grower then a plant and you will see results dramaticly improve. Check the grower first then the plant second. I say this because of 10 grow seasons and friends with combined 75 years. The grower is always the cause/origin of most problems and adding more wrong things. To the damage they caused anyway is standered practice because we dont know any better!! Imagine if you took 10 / 15 multi-vitamins every morning with a cup of coffee. Your body will use only what it needs and the problems accour with the un-used/prosseed parts. They clog or cause damage because of the left over ammounts

Thanks for the replies,
i was really after someone who has grown with CO2 and can give me an idea of issues (current and unforseen) that i may run into. from research i am under the impression that CO2 requires more nutes not less, i have grown the same strains for the last year with and without nuting but the CO2 has added another twist.
cheers again
GG