calmag?

Is this your Lost Pearl grow? You've nailed the problem (calmag) but I wanted to know WHY you had this happening... you need to know why before you can fix it. I don't see your information on the pH level and this might be the culprit - make sure you're maintaining the pH between 6.0 and 6.5 - 6.2 being the "sweet spot." Nitrogen toxicity creating a lockout is also one of the reasons growers get a calcium deficiency - but I don't think that's the case here as her leaves aren't a really dark green and you've switched to bloom nutes only... still, there might be sufficient nitrogen left in the soil that's causing a lockout. I would say to add some calmag (1tsp per gallon once a week) - if you continue to see the problem growing, you might consider a flush putting in your bloom nutes and calmag with the last of the flush water. Good luck!