The Master Blend is close to what I use.
I use Chem Gro x Hydro Gardens
They use a base of 4-20-39
Then add Calcium Nitrate.. 15.5-0-0
And then I add Epsom Salts
Your Master Blend formula is the same as Chem Gro Tomato formula.
Weed likes 2x the amount of Potassiun vs either Phosphorus, or Nitrogen.
Chem Gro came up with these ratios from tissue analysis, and have also been making pplant specific fertilizers, and greenhouse equipment since the 60s. One of the oldest greenhouse companies around.
Its a myth you need to change to flowering formulas when you switch to 12/12
Most of these flowering fomulas cut way back on Nitrogen, which is a proven mistake.
All Nitrogen is, is Protein. Humans eat Protein, and our bodies turn it into Nitrogen. Thats why Bodybuilders, and other athlets eat frequent meals with all the basic nutrients. Its to keep our bodies in Positive Nitrogen Balance. If not, we sttart cannabilizing out own muscles, for energy.
When one switches to 12/12, the plant is going to be putting on more mass, producing more hormones, and growth during anytime in its life. It makes no sense to stop, or cut back on Nitrogen.
Protein basically means of first importance. It is the most important Macro Nutrient.
All they need after flip is an ever increasing PPM of thesame formula as you give them in Veg... Chem Gro has you add your own Epsom Salts to the mix.
In weeks 3-6, for an 8 weeks flowering strain, its beneficial to add Monopotassium Phosphate. Then the last 2 weeks before harvest cut back on all the nutrients to around half sstrength. No Flushing.