Hi Greenmachine81, Signs of magnesium deficiency • The oldest growth will be affected first, meaning the lower parts will show symptoms first, with new growth being the last. • The leaves turn yellow and the contrast between the green veins and the leaf surface is significant. • Once the leaf has turned yellow, the tips become rust brown, because the leaves are smaller.

Gonna need a lot more info. Are you growing in soil? Whats your ph? Nutes? Temps ect it from what I can see you have multiple deficiencies. Nitrogen, phosphorus, calcium and probably more. When you have this many things showing up the problem is almost certainly a ph issue causing lockout. If you provide more information that would be helpful