Purple Stem?

[CP316]

I got an auto candy cane and its at flower stage, and today I noticed there are few purple stems, Is the purple stem Magnesium Deficiency? I used PH 6.5 tap water and also I do feed with 2ml Cal-Mag for every single feed. Should I increase the calmag to 4ml?

 

[Metal Halide]

I lower PH a bit but other than that they look great. Carry on

 

[Hdinkleman]

its fine

 

[Nunyabiz]

If there's no other symptoms then its likely to be genetic.
I'd just keep doing what you've been doing as they look just fine.