How often should I be using calmag

Organoman is right... both in terms of how often to use calmag and in terms of what it does and does not do. You haven't been feeding enough! I've gone through a couple of weeks of your diary and can see the amount of nutes you're giving her hasn't increased at all since at least week 3.... you've added bloom nutes but that's not enough here. This is a bit tricky, to be honest, because you're growing an auto and she's definitely in flower... Autos don't like a lot of nutes which is why you start them off slowly to see if they're going to be tolerated - and they were (pics from week 3 show a beautiful, lovely green plant) - but then you need to increase them. Once they go into flower, the nitrogen needs to be reduced and the bloom nutes increased.. they need less nitrogen in flower than they do in veg... but yours look like they would still benefit from a bit more nitrogen even now. So let's figure out what you should do.... If this was my grow, what I would do is to double the amount of the BioGrow and triple the amount of BioBloom for one week. Calmag is not needed but won't hurt as long as you don't use it more frequently than once a week or even once every two weeks. Next week, I would reduce the BioGrow SLIGHTLY and keep the BioBloom going at the new dosage... the plants are going to need a lot of PK and the bloom nutes are designed to do just that. You should start to see the green coming back and the plant not looking as pale... and she should start to do some serious stretching although that's not guaranteed. If you see the plant become TOO dark green, cut the BioGrow back down to what you're giving her now and when you water, make sure you're getting a good 10-20% runoff... Good luck with her!