Yellowing

Could also be a zinc deficiency but rare.

This is overfeeding - high levels of N and will lock out other nutrients- specifically calcium here.

Your ppm is wayyy to high my friend. That is why your plants look like this. It's nutrient burn, not a deficiency. And cal mag extra has nitrogen as well so you're over doing it. You should cut that down to at least 1000 ppm and even that's aggressive my guy. ( I would go 750). I hope this helps bro

Leaf septoria, also known as septoria leaf spot or yellow leaf spot, is a plant disease caused by a specific kind of fungus known as Septoria lycopersici. This fungus usually overwinters on dead foliage or common garden weeds. Fungus spores can also spread onto equipment like garden stakes and netting, before germinating when conditions are right. Leaf septoria can be an extremely damaging disease, greatly affecting the foliage and growth of a variety of plants, including tomatoes, parsley, and obviously cannabis. As the name suggests, leaf septoria is characterized by yellow and brown spots forming on both the upper and lower sides of leaves. The spots tend to be circular with dark brown margins and tan or greyish centers. They usually measure between 1.5 to 6.5mm. Leaf septoria usually affects plants just after they enter the flowering stage and usually forms on lower leaves first. As the disease develops it spreads its way upwards, quickly affecting multiple leaves all across the plant. Affected leaves will usually turn slightly yellow, then brown, and eventually wither completely. Leaf septoria rarely spreads on to fruit, so it generally won’t affect cannabis flowers. If left uncontrolled, the disease can destroy a lot of foliage. This ultimately creates a lot of stress for plants and stunts their growth as well as the size of their harvests. Leaf septoria is particularly prevalent in areas affected by extended periods of wet, humid conditions. https://www.royalqueenseeds.com/us/blog-leaf-septoria-yellow-leaf-spot-on-cannabis-plants-n678?_gl=1*zj2hsn*_ga*Mzc5OTUyNzIwLjE2Njc4MzMwNjU.*_ga_MFLBPT8N0L*MTY3OTM0MjAxNS4xMS4wLjE2NzkzNDIwMTUuMC4wLjA.