Day 42 of GG bloom and the Buds are starting to ripe so I starting to flush my concern is that promix-hp is inert and all I’m putting on them is water is that ok
You may not need to flush yet. Just use plain water the next couple waterings and that should let the plant use up what is in there. Do you have any pictures of where you are currently in the grow
I use Promix HP (great stuff) and the only flush I do is the final push before harvest. I do water to runoff–like 20% and interestingly talking to @Not2SureYet pointed out he gets best growth spurt after a watering and not after a feeding.
You should also find the interval that the plant is most happy with: Feed/Water/Feed/Water is recommended but you can run F/F/W/F/F/W or more. I PH right to 6.0 and get decent N transport all the way to harvest.
Florakleen is a great product for any flush as is Sledgehammer.
What nutes? What PH? What is your TDS in and out?