CalMag deficiency?

Not a deficiency of any sort...........this is burning caused by a salt build up in the substrate. Generally occurs when people irrigate incorrectly by not getting adequate run off each time they irrigate and only water in small amounts near the stems in some sort of strange fear for "over watering". Overwatering is watering too often, it is not not watering deeply and to run off. Cal mag will not solve this issue.............make sure to get 10-15% run off each time you irrigate to prevent it getting worse, but the build up is already there.........you can only prevent it by watering properly for your entire grow........right from seedling stage. Do not "flush" or try any other sort of weird treatment, these can often cause more problems than they solve. Plain water for a week should help reduce symptoms...........but you must always get run off............then resume feeding gently.