Bud Boom is an additive and doesn't have all the micro nutrients that your plants require so you're bound to see deficiencies. In late flower before you start flushing, I would still use a base nutrient, such as Holland Secret by Future Harvest.
there's an OMRI listed organic calmag from Future Harvest Nutrients. It's called Organical Magic. Apparently it's 100% water soluble so it's immediately available to the plant.