Plants are on day 75.Banana Purple Punch. I watered the short plant with a pH water of 6.5 and 800 ppm.I watered the tall plant with fertilizer and 1100ppm

Flushing is a myth Darkness is a myth Ice bath is a myth Any stress added in last few days is a myth, the plant can't react fast enough to increase production of trichmes especially if it has no building blocks "nutrients" left in the medium or light to power the plant to build them. Its just pure Bull Shit. If anything give it 24hrs of light last few days and then chop it and dry in the dark. It could produce more terps but that's about it. Grow em like your in any week of flower. lights on and feeding them, just less. Tapper your feed in the last two weeks down to 1/4 or none at all and just give them water without excess runoff so they can use up whats left in the medium, runoff just starves them off. Alternatively you can feed them like normal but the plant will not use it all and its kind of wasteful. It won't build up and cause it to taste chemically. that's dumb and not how it works. Also your CO2 bag is not doing a lot of anything and extra nothing that high up next to the extractor fan. Its literally sucking the little amount of CO2 it's making out of the tent when it extractor is on and TBH its not making enough of anything to be effective. Indoors CO2 levels are already slightly elevated and that does most users just fine. Depending where your venting to also effects things. If its your living environment you don't want extra CO2 in it. If its outside that better. Propper CO2 assisted grows are in a closed loop system meaning nothing is vented out and kept sealed in that room. The air in the room is cooled and dehumidified with a CO2 controller adjusting the levels. 1000-2000PPM ish, average CO2 in the air is around 400PPM depending where you are. Just ditch the CO2 and save yourself some money. its not worth it. Only pro growers with a massive setup should be using it and that's after they have everything locked in.