brown rust spotting on older leaves. Cal/mg def?

These plants are about a month old in RDWC 25 gal system. I'm using Lucas GH micro/bloom at 8/16 with RO water with nothing else but EWC tea. I've read where people say Lucas has enough cal/mg in it and you dont need to use anything else and I've seen people on some forums consider 6/9 micro/bloom as what Lucas should be in DWC I assume to add more micro for cal/mg or N? So for a about a week now I've had these brown spots which started at the very most bottom fan leaves from the first node and are now moving up the plant slowly. My PH is 5.8 all the time and is very stable so should I be moving it up or down to get better uptake? I see some charts say Mg isn't absorbed untill above 5.8 and Mn not untill below 5.6 I think. Am I just locking out something or do I have a deficiency?

Is there anything else that you are doing? Foliar feeding? Do you mist the leaves? Does water get on the leaves ever? What is the PPM? I use GH Flora Micro and I still add the recommended dose of Calmag.

I dont foliar feed but sometimes I drip water on them when im watering the hempy or just doing maintinace. If I add cal/mag and they dont need it could it become toxic? I'm ok with adding it and not needing it as long as it wont hurt them even worse. My PPM is around 1050 with RO water just like anyone else using Lucas would be on .5 scale. Does the dmg look like its from dripping water on them when I'm in the tent or cal/mg issues?

So you use Lucas with GH micro/bloom and RO and still use calmag? I went and got some calmag and silica blast today cus I need to get this sorted out before I goto flower and have even bigger issues. Should I foliar feed them some cal/mag?