Hey bud, love your log so far still reading but wanted to pause and take a moment. You asked the question about cal/mag using it every feeding. Please some one correct me if I am wrong here, but I do think he should be using cal/mag during every feeding. He's in Coco, ph of 0. So what you put in is what you get out. The cal/mag is what you use first. I have always used it first and never ever had an issue with cal/mag. Even more since hes running under an LED light. LEDs are known to have issue and cause cal/mag issues. It's a base its pretty hard to over dose with it. I understand if you mean at the start, but this far into the grow I think cal/mag should be in every watering.
Your later pictures with the purple stem, that is starting to lead to a mag issue. I read that you soaked your cube in cal/mag before glad that worked for you, never done that
. But I really think every watering you should have that. 5 ml per gallon.
Love your set up, man it's going to be interesting what you can do in that small tent
. My older set up was kind of like yours. I used coco for a while (Just moved to hydro) I loved coco was great used them in 3-5 gallon smart pots. I also use 2x California light works 440W(Did that so I get 2x the T8 bulbs + I like breaking them up.)
Question for you, are you using maxigrow or maxibloom atm? I haven't used this line from General Hydroponics I use mostly the Trio + other things from them. But shouldn't the maxibloom be used in the flowering stage? And maxigrow be used for veg stage.