I've been using calcium nitrate as my nitrogen source for years. It's great for growing in coco. It provides all the calcium needed. I've never used a drop of calmag despite all the people saying it's a must have for growing in coco. I use it from start to finish.
I've never used calcium chloride to provide Ca because I wouldn't be able to get enough N without calcium nitrate. Calcium nitrate is the primary source of nitrate in most hydroponic mixes because you can only use so much potassium nitrate before you have way too much K. There are 2 nitrates for every calcium ion but only 1 nitrate for every potassium. You get almost enough K just by using mono potassium phosphate for P and thus only need a little bit of potassium nitrate.
