Hi there, I'm currently growing Northern Ligh...

Firstly based on reading your stats , your in a soiless medium and your running your PH at levels that are for soil . I would advise that you lower your PH slowly to a more soiless range (6.0 - 6.5) one thing to keep in mind while lowering your PH is that you wanna do it slower and over time if its to sudden you will cause all sorts of problems for yourself ( Nutrient lock outs , nutrient burns , stunts in growth ,ect...) Secondly you wanna make sure that its actually CalMag def , sometimes a plant will have multiple pheno's and these will often be displayed by big red lines in the side of the main stock they usually look very very uniform . However if your notice the stems to your leaves getting red/purple or the center of your leaf were the stem connects starts to get red/purple then you know CalMag deficiency is the culprit another sign you can look for is yellowing in between the vains of your leaves this will also indicate CalMag deficiency . After you have figured out if its a different pheno or not , if CalMag is the problem add 2ml/l for the next little bit and you will see your problem slow then stop all together . I hope this information sheds some light into your grow and helps you understand how you should lower your PH and what to check for to make sure its CalMag deficiency as well as the simple solutions there are to fix the problems :D :D -Happy Growing!

Hi there cococola, so there's two things causing this red stem, but the good news is you caught it early and you will be able to fix it ! so you have a pretty "high pH" , you should be at pH 6 , not 6.8 and in coco you need to add micro nutrients for example calcium and magnesium. So essentially you're getting stress from not having calcium and magnesium which are pretty important to have in coco. Simple solution to this problem, start adding calmag and pH down to 6.0 the plant should recover in 10 days. hope this helps ! 🚀