Mint Jelly and purple haze in 2x2

neither plant is absorbing nutrients. For example, the MJ got 1.5 gallons of 250ppm nutrients 2 days ago, which is already very low, and then today it has about 1 gallon left at 400ppm. So, it drank a gallon of water but ate nothing. It is now getting just pure RO water. The PH only stopped absorbing nutrients in the last 2 days, so I'm giving it half strength nutrients. My plan is to go another 5 or so days, then switch both to pure RO water for 2 days, then harvest.