sometimes overflushing, I have heard, can leave you with dark ash/inconsistent burn.
I really flush closer to 5 days tbh, distilled water, and more focus on drying the plants out than running massive amounts of empty water through the medium. Once the nutrients are gone there is nothing for the plant to take up even if it was trying, so in my mind at this point, after you have flushed the medium of nutrition, any water given is to help the plants retain some turgor. The flushing process at this point, to me, takes place inside of the flowers. The plant, hypothetically, uses any residual excess nutrition within itself, leaving a smooth, salt combustion free smoke.
The only use diluted water has is to dilute and remove any residual nutrients in the pot, the plant is not retaining water void of nutrition, it is using it to support itself and then transpiring it off.
