I think that I have a very similar question/situation. I have 2 pots that have a 2.5 gallon reservoirs each ( full of healthy looking roots). I mix 5 gallons of nutes full strength once a week and top off with ph'd water with calMag or Liquid Karma based on Latewood's legacy nute schedule. I go through close to another 5 gallons of top off each week. I then completely drain the reservoirs and start over. What are other people's thoughts?