works great for me, i use throughout the 2nd half of flowering @ 2ml. per gallon. turns everything very frosty and is way cheaper than the purple maxx. I use it with gravity all the way until the last week. They also sell a p/k now called sonic bloom( 0-51-34 With B1, b2, b3,b6 ) that I have been trying with good results. all there additives are pretty cheap for what they do.