she could easily hit 7-8 zips ++ if you listen to her needs, and id drop the rhizotonic at this stage of the grow as its done its job, the plants do still put out more roots in flower but not at the same rate as they do in veg so you might aswell save it for another grow, ive got to the stage now where I don't even use root stim
also I noticed your using cannazym which does break down your roots as this is taking effect it will increase your ec, if your res temps are ok and your pumping enough 02 into your res your should never have to use cannazym, ive never used and I do get amazing root formation
if it was me id just use canna flores / cal/mag and boost and then monitor my ec and ph as I know she can take a stronger feed but because of the zym this might be throwing your whole res out of sync, you didn't mention anything about which direction your ph was going as this is also a great indicator of whats happening in your root zone ?
also to get even deeper the cannazym might actually be killing your plant slowly as it doesn't just eat away at dead roots it will breakdown everything so even the healthy roots maybe taking a battering which is why your plants look like they have tip burn but in actual fact its because the roots that are suppling that part of the plant have been killed
im sure after reading this you will see im not a big fan of anything that will kill my roots haha
seymour