Leaves yellowing

I have the funny feeling you've given it far too much calcium, tbh.... this is a difficult excess to identify BUT too much calcium will actually cause a lockout of potassium, magnesium, manganese and iron - which I think is what you're seeing. If this was my grow, I'd probably do a flush (3x the water as pot size) adding in nutes for the final gallon of water you put through but only 1/2 strength - and NO CALMAG.. make sure the water you're running through her is ph'd between 6.0 and 6.5 (closer to 6.0!). Calmag is way overrated as far as I'm concerned and too many people, when faced with any issue, turn to it as a panacea which it isn't... and it's a nute that's easy to over-do. The only time I would use it is if my grow was showing a deficiency and I KNEW my ph was sitting at 6.2... but calmag should only be given once a week and AS NEEDED... Put it this way... I've done many grows (far more than I have diaries for here) and I've gone through MAYBE 6 tsps of the stuff... wish I had never bought it! As long as you maintain a good PH, you really shouldn't need additional calmag! Good luck...

If your in soil then up your ph. Soil ph 6.0 to 6.8 Hydro/coco ph 5.5 to 6.5