Koolbloom is a bit strong. (edit: It also costs to buy it as an 'extra' product)
I do the "H3ad" thing and use around 23ml of GH Flora Bloom instead. (would use more but I get burning when using the Maxibloom as the base nute).
I already have it and it HELLA denses up the nugs and packs on weight. The side by side was VERY noticeable.
Only twice in a flower run.... day 5 and about day 45, depending on strain.
Stay Safe!
23mls per gallon! thats waaaay more expense than using koolbloom in my 50 gal rez that would be 1150 ml of FNB costing like 35 bux