Word up on that brotherWhen adding cal mag to ro water you are only replacing what was removed in the ro process 5ml is way too much in any case, you only need ~100-150ppm added to the water and that's ONLY if you are using the water alone. If you are using a complete formula like dyna gro all that is already included in the formula.
Additional magnesium isn't required either.
ok so after I read this comment, I looked directly at your avatar picture and just about spit my coffee on my laptopI never follow what the bottles suggest as that's always too high. I use RO water and use 1.5mls per gallon of grow. I also add 3 mls per gallon of Protekt to balance out the pH and to provide the plant with silicon.