Dealing with nutrients problems

[Jgrower223]

Hey I'm gonna put a couple picture of what a couple of my plants are doing while other (which are different strains are not having these issues)

I'm starting to do think I need to flush my plants because I've add cal-mag thinking it was a secondary nutrient Deficiency but its continuing to get worse the first picture has happened to all my plants but now it's down to just one. Where the leaf yellows then dyes. The next few pictures are 2 lemon OG plants and this started at the top of the plant and I have yet to stop the problem. I don't want to flush them and find out I'm wrong so any help would be nice.

 

[The Phantom]

If you can, try to grab a few photos of the plant under natural light, it makes it a lot easier identifying these types of things.

What are you growing in, is it growing hempy style or just a lot of perlite of the top in the photo? What are you currently feeding your plant for nutrients, how much, and how often?