flowering

I just switched plant to flower stage of 12/12 and looking great. wen should I start with bloomblaster. I have never used anything before but nutes straight up to last 2 weeks before harvest. also....should I continue the regular nutes I have been using? last watering was just an easy "bathtub flush" HELP.....it's time to water!!
don't wanna shock my baby now!
thanks for any advise

I would switch to flowering base nutes when you get a little puff of pistils in the tops. Not sure what bloomblaster is, but pretty sure you don't need it. Be careful using too much P.