Before cleanse, The plant wont lockout. It will simply burn its stores of energy, and NPK. Which would look like lockout. The PH debate has gone on for a long time, when its time for the final cleanse. I do NOT ph my water to cleanse the plant at the end of the grow. It is my opinion, that you should not, and do not, want chemicals(ph up and down)in your plant before chop. You let the plant canibalize itself and use up all ist own stores of NPK and it put the plant in survival mode to create more trich's and fatten up before its life cycle is over on its own stores. All I can suggest is to do 1 plant with ph cleanse and 1 plant with plain tap water and separate them for drying and be your own judge. Also, don't want any mixed feelings on the matter, but you dont have to keep your plant in total darkness for 24-72 hours before chop. That business is a myth. I do however feel like you should chop your plants before the light cycle turns on. Just my "My 2 cents"