I did a full grow using Lucas Formula. I didn't use cal-mag. Lucas is meant to be a cheap and easy complete food source, even though it technically isn't.
I'd start off without, if you see deficiency then add, the general rule with most food sources is to start with 1/4-1/2 strength and work your way up to full only if necessary.
My mistake, I never bother to look these things up directly, I just ask people I consider experts.The mixture is a complete nutrient solution it is just not a properly balanced nutrient solution. It is ones of those "it works well enough" methods commonly accepted by unknowing growers as good.
The Lucas method (not the Lucas Formula ast here is no such thing as a Lucas formula just a GH formula used in a foolishly suggested manner by the dim wit Lucas). The mixture is a complete nutrient solution it is just not a properly balanced nutrient solution. It is ones of those "it works well enough" methods commonly accepted by unknowing growers as good. You are much better off using all three parts as directed by GH just use lower strengths then recommended. You also must remember an EC measurement converted to ppm is not a true ppm measurement but just an estimate based on the solutions ability to carry an electrical charge. Believing it is a true ppm reading can quite often mean over fertilization.