Yes but if you use a
nutrient designed for flowering.fruiting plants to begin with, it will already contain all the individual elements in a balanced nutrient, including enough Phosphorous for flowering/fruiting plants. If you just start tossing in stuff Willie Nillie, you wind up with toxic levels of some and depleted levels of others. The reason RAW
nutrients don't create balanced nutrients to begin with is so they can get you to buy lots of overpriced parts to it to get more money out of you. As you've already found out their just overpriced, that's why their not on my list of cost effective nutrients.