Just a couple of things. At 1100 ppm I doubt you are under feeding them.
Calmg is the most over diagnosed problem on these boards. Seems to be the fall back problem for everything. With that many additives I truly doubt you have any kind of deficiency. If anything a toxicity of something. Mg will pop up on a ph issue not Ca. Sunshine #4 is a peat based mix. Peat has a real low ph. Sunshine has alot of lime in it to buffer it. Following foxfarms schedule will put your nutes a little too high unless you are in hydro.
Yea man I thought I had Fungus gnats with the same exact symptoms as you are showing. Started in veg. Hit them with BTi and that knocked them down but not out. Azatrol dunks seems to get them almost completely gone for about 3 months after that. Then flower rooms yield got cut in about half. Again thought I was fighting a gnat problem. After reading that thread all the way through
on IC and taking my ladies advice I realized it was aphids not gnats.
Just check you medium. Dig up about the top 3 or 4 inches and disturb it quite a bit. Then look real close on the side of your pot and in your medium. You will see them if you have them. Some plants will hit hard other will almost look unaffected.
Mystery nute problems that cannot be fixed when you know you have the right PH, conditions, nutes and environment it is most likely a bug or something worse like a viral or fungal infection. I know alot of people will try and not believe the worse but sometimes thats the case. Bite the bullet. If it ends up being aphids dont bother with the bio controls, neem, pyrethrum, ect. I used Triazicide at 11 ml per gallon. Fucking genocide in my room. Nasty chemical. These are not getting flowered for a while so now was the perfect time to hit them with a nuke. Saving the Bayer if I need it. It could be another problem but check that road to save you time and your moms/crop. Best of luck and crossing my fingers thats not the case.