First SuperBox DWC Auto Grow

End of week two. Still a learning process. I was getting some Temps in the low 90's high 80's and pH was rising fast. I moved the air pump outside of the cabinet on the hopes of creating less heat inside whilst pulling cooler air from outside to pump inside the rez. The pH seemed to stabilize after this and Temps lowered. Still mid to low 80's but better than what it was. I also added a pc fan to pull more air from outside to inside. Temps haven't breached 84F. Plants are starting to have a little smell to them which is heaven to my nose. Still unsure about ppm. PH/nutrient solution was at 1080 per 2G of water. It's now hover in the 960-980. Good or bad I don't know. They're drinking about a gallon every few days. I have been topping off water only when level drops from 2 G to 1 G. Also added 1mL of CO2 solution to the water as an experiment. I'll update on that next week. Sunday morning both Kush strains showed some flaky spots. Not sure what it is yet. If someone could chime in much appreciation. Because I'm a noob. Not an idiot. Just new. Also noticed a couple yellow tips here and there. Should I be concerned with the tiny bit and cut back nutes?