Preharvest DRAINING stage.

Dear all Expertise Growers,

I have been cultivating Hydro with rock wool lately and I need to get feedback on the last draining done last weeks of flowering as I have been draining with ro water at aprox ph 8.5. for 14 days.
However the ash when smoked is not turning all grey but more blackish than grey. I am trying to get it to its lowest amounts of nutes still in the plant as it nears its harvest.
(I've gotten better results on other strains, could that be a factor? the strain?)

Any techniques I should be aware of ? Is there anything that I might be missing in my procedure??

By the way I am curing it at 70 degrees for between 15 to 20 days.

I would appreciate your response ,
Thank you
Cannabyte

pH 8.5 sounds way too high for healthy Cannabis.

I grow in soil and prefer my pH from 6.2 to 6.8.

Not overfeeding during the entire grow cycle helps in creating nice burning ashes.

This is strictly my opinion so take it for what it’s worth. At 8.5ph you’re locking up everything in the plant. If you’ve been feeding at a ph of 5.6-5.8 then suddenly switch it to ph 8.5 it throws the plant seriously out of wack. It won’t use up the nutes stored in the plant itself so the water isn’t helping it. It just kinda shuts down. My question to you is why are you using such a high ph to flush instead of the same ph you used to feed normally with?

I used to run 4x4 rockwools. Ph at 6 the entire time with the last 10 days getting clearex and pH water.