I dont know anything about the fertilizer youre using, but I do know its a myth to cut out, or lower Nitrogen during flowering. In reality plants need more of everything until about the last 2 weeks before harvest.
All Nitrogen to a plant is, is Protein. When plants flower, they are putting on more mass, and growing more than any time during their lives. They are also producing more hormones at this point. Protein/Nitrogen is also responsible for cell division.
If the fert company you are using also makes a veg formula, you might combine the 2 to give nitrogen.
I use Hydro Gardens Chem Gro chemical fertilizer, and the basic formula stays the same until the last 2 weeks before harvest. What changes is the strength of the mix. In an 8 week strain, EVERYTHNG is increased until week 6, then fert is cut back for the last 2 weeks.
The formula I use is
4-20-39 Mixed with Calcium Nitrate-15.5-0-0 and Epsom Salts. Then in an 8 weeks strain, in weeks 3-4 I add Monopotassium Phosphate. 0-52-34. Weeks 5-6 they get a boost of extra Epsom Salts. I use Promix BX as a medium, and use small-medium amounts of fertilizer at every watering. I use fertilizer as son a seedlings pop up out of the soil. Usually at 10%-15% strength.
But if your fert has 0 Nitrogen, youre going to have big problems. Hydro Gardens says going by tissue analysis weed needs as much Nitrogen, as it does Phosphorus. 19.5 vs 20, and 2x the amount of Potassium as Nitrogen. They have been making fertilizer since the 70s, and plant specific fertilizers since the 80s.