Cal/mag def. Or nute burn?

Hi there Weisass, sorry i have to disagree with my growmies here. It's not magnesium deficiency because this will cause yellowing from the newest growth first because it's an immobile nutrient, and from the edges of the leafs first. You can see you have a potassium (k) related issue because of the colorful (rust) colored discoloration starting on the bottom leafs first. But as you know and you can see you're already giving bloom nutrients. however the NPK ratio of your nutrients is too heavy on the K, so actually it's causing lockout. This is one of the most difficult problems to fix : you do need flush , probably you need to water with plain water a couple of time, then you need to rectify the NPK ratio, right now you're giving 3-12-6 you should be giving something like 6-12-12 or 3-6-6 , something simple like that. I hope this helps ! 🚀