Rainbow Chip Exotic Genetix

Day 57 - Still growing like crazy but I am having some issues with some fan leaves. Would some calmag help or does is it look like a fungus/disease? Hi guys, I'm hoping I can get some more help on my grow. I noticed these rust looking marking on some leaves. It's not spotting but more of patches. I have been using the general organics line and just got feeding up to 100% of their recommended dosage, minus calmag. I have a flower tent next to my veg tent. I started to add co2 to my flower tent 10 days ago and I was exhausting the air from my flower tent into my veg tent. It helps keep temps up in my veg tent and allowed me to supplement both with co2 pretty easily. At night time, I exhaust both tents passively with no c02. These spots are appearing primarily on the plants which are right below where the exhaust comes in from the flower tent. Are these spots from a deficiency or are they from a disease/fungus caused by the environment I created? I did run out of co2 the other day and I am waiting for more. Meanwhile I am still exhausting the flower tent into the veg tent during the day time. Could this be causing the problem?. I am having a rust like color show on a few fan leaves. I gave them some water and calmag yesterday. It appears to have stopped spreading but damaged leaves did get a bit worse. I also used a coco potting mix blend in a few plants to compare and I am wondering if that contributed to a possible calmag deficiency.