Do you ever need to use calmag at all?
Yes , always with LED runs apparently. I compensate by keeping grow temps up higher as possible . Calcium helps the plant’s stoma process and plants transpiration.
The number one issue growers have when switching to LED is their grow room temperatures. Leaf temperature is the actual parameter that ambient/air temp is influencing, and different lighting can effect the leaves differently. With HPS and other HID bulbs, they contain 2 forms of heat. Convection heat from the excited gases temperatures in the arc tube, and also IR energy that is radiated in the beam of light itself. IR heats surfaces on contact, and has the most impact on leaf temperatures. HID growers are forced to lower their ambient temperature to fight the IR heat in order to maintain ideal leaf temperatures(both surface and internal).
LED’s do not emit IR and as a result, do not heat up the leaf surface, in addition to their general heat load reduction they offer. To maintain ideal leaf temperature keep metabolic rates high, growers need to run an average of ~5-8˚F higher ambient temperatures than in their HID environments, targeting 80-85˚F. With the higher ambient temperature, the internal leaf temperatures are maintained in the ideal range for vigorous growth and nutrient uptake can take place.
I notice my plants prefer 80°+ ( type of temps during lights on ) and roughly about 10-12° less at lights out. I have had to keep containers off of cold flooring , warming pads , etc. during cooler times.