Light dry spots on leaves

hey there Kurow, you're right to look at the humidity, but it turns out you have a more serious problem. In fact the discoloration is due to pH fluctuations. you can tell from how there are different shapes and sizes on the spots , the red stems and downwards pointing tips. Basically fox farm soil gets this problem quite often, i've seen it a hundred times. Try to get a pH meter or better yet, pH strips , and measure the pH of the water/feed going in and going out. you should be at 6.0 going in and 6.5 going out. my guess is that the soil is not buffered correctly so you'll see you're outflow being much higher than 6.5 . Get some pH up and pH down, then pH appropriately and it should take like 5 days to a week's time to stabilise and the problem should stop spreading. Hope this helps ! 🚀