Buddy2
You use cal/mag every watering and feeding.
Cal/mag is basic nutrients that come in natural water.
Now the real question is what kind of water are you using?
you would only need cal/mag if you are using R/O water since the nutrients are filtered clean from R/O water.
If you are using something like tap water then your city has already added those basic nutrients in the drinking water.
So if that’s the case don’t use cal/mag unless you have a cal/mag deficiency
it is always best to use R/O water and add cal/mag yourself so you can have fresh clean water and control your ppms. 
Use 1 teaspoon Epson salt added to a gallon water and the leaves will straightened out soon after.