Are you using RO water or tap water? If you are using Tap water there is no need to worry about Cal/Mag. I've ran this line for years and never supplemented Cal/Mag with great results and actually H&G will tell you to only use a Cal/mag supplement if you use RO water. Are you using the complete line or just Coco A&B? If so you just got an amazing line. If you would like check out my grow I have it posted in my sig below I run the complete H&G line.