My large holding container holds 22 gallons, my watering bucket is a bit less than 1/2 gallon. I basically use up the entire holding container with each watering. I DO NOT WATER TO RUN OFF. Use a good organic fertilizer, run off does not matter. Actually, can't remember EVER watering so it runs thru the pots, except maybe flushing in the end. I put in just enough, and not more. I want to control the humidity, and by having H2O sitting on the floor all day/night, that would be nearly impossible.
As usual Dr., you are asking great questions and questions I don't get asked normally.