Clones of BNL

As you can see in the pictures, I have a cal mag issue and it kinda sucks! Is it a Ph issue? Is it because the tent is getting pretty cool at night? Or is it the nutrients/build up? I flushed them pretty good once I really started see the issue came through. Like last week i could see come issues but in the middle of this week I could really see some leaves taking a turn. Im lowering the dose of my nutrient and will likely feed them less. My yield might not come out the greatest now but its ok. I want to fix this issue so the quality of my plants is on point. These ladies have added some serious weight in the last week even with these issues coming up. Good frost and they are getting smelly. Hope the next 3-4 weeks go well. Happy growing.