@legalcanada I'm using a different brand but it's a very similar product.
Their in house brand is called Chem Gro.
They have a 'hydroponic special' mix that's 5-11-26 with micros. It's designed to be used with calcium nitrate and epsom salt, aka magnesium sulfate.
Cal-mag is calcium nitrate and magnesium nitrate, so it's not so dissimilar. I think you end up with too much nitrogen and not enough sulfur if you use it instead of the recommended salts above.
2 parts 5-11-26
2 parts calcium nitrate
1 part mag sulfate
Mix calcium nitrate into solution separately from the others. Mix all into solution before adding to the nutrient reservoir.
I have run as high as EC 2.6 (1300ppm @ec x 500) but I'm currently getting great results at EC 1.5 (750ppm), pH between 5.6-6.5.
In my experience, mag sulfate is the preferred supplement because so many of the desirable resins and terpenes are themselves sulfates.
If you have any more questions I'll be more than happy to help.