Cal mag deficient or toxicity experienced coco/perlite grower help plz

I was told if u have purple streaks on stems but plant is healthy it means u have to much cal mag now I’m told not enough which one is it from an experienced grower not a guess I’m really trying to dial my shit in I know experience is best teacher but good advice would very much so help before I flip to flower I use ro water and I run in 70/30 coco perlite
If I’m mixing up 4 gallons of nutrients should I be using 5ml a gallon so that’s 20ml of cal mag plus or should I be using the lower dosage at 3ml a gallon plants otherwise look great but did notice some streaming of purple I was told so many things stress from growing and training cold temps ph etc but temps stay on point Ph is between 5.5-6.5 whole grow is thier an optimal feeding to absorb calcium etc I feed at 5.8 5.7 6.0 varying times

Also what should a healthy ppm be should I be low 400’s or higher? When all my nutrients are mixed I was told less is more and so I have been mixing at half strength maybe that’s fucking me up but I’m asking so I can correct it much appreciated thank u everyone as always

Idk either way, but I’m experiencing a lot of purple in my stems/veins right now and I haven’t added a drop of calmag to my soil. So maybe a lack of calmag if anything? I know the bud that I got this seed from was crazy purple, so I’ve been attributing the purpling to the genetics so far for my situation.

The second picture the purpling is higher up in the branches once again thanks for your time and help!