hey turtelz. the plants will really use a lot of phosphorous in early-mid stage of flowering like 2nd through 6th week primarily I'd say. If you are already on week 8 you should've already been flushing(if you didn't grow completely organic) or just switching to water. I like bat guano high phosph that Fox Farm makes. Its a good top dressing to use in flowering as well as a nice additive to your original soil.

:rastasmoke: peace