@Fisch Currently they drink about 1/2 gal of water per plant per day (2 L / plant / day). I top-off their reservoirs every 3 days. The air pump is an 253 GPH (958 LPH or 16 LPM). Its nothing special but gets the job done and very quiet. The one pump is used for both plants and I use a T connectors to change from 4 port to 2 port. I use a 6 inch circular air stone to distribute the bubbles and control the water temp with an 50w adjustable water heater for an aquarium
Don’t get me wrong, there are plenty of perks about growing in soil, however once I did hydro I never looked back. Like, flushing in hydroponics is great and goes with the maintenance schedule of cleaning the system and changing nutrients. Its a little more work and maintenance about every 2 weeks (that’s when I do it anyway). I personally find it satisfying to work in a soil-less environment.
One thing I will mention is the plants are more sensitive to there nutrient solution. Deficiencies, toxicities, and PH imbalances are noticed quicker and more severe. However, you are also able to correct them very quickly as well.
I heard some where that; its not the plants that get over watered, its the lack of oxygen to the roots…That’s why having the constant tiny air bubbles over the roots makes it possible for them to be submerged all the time. I donno, I claim to be no god, just a dumb mortal human 
How much they drink a day? What pump do you use? How many Liters of air in minute or Hour? I envy you the flushing in the end. That must be really easy to clean them up in finish 
