The more water you have the more stable your solution will remain. Balance that thought with hauling water around.....but also keep in mind that changes inside the setup can cause GREAT damage to your plants. If you don't mind checking and adjusting things several times a day you can go with smaller water amounts. Hydro does NOT leave a lot of room for mistakes. Most people llike more nute solution available as ph and nute numbers remain much more stable, healthier and generally safer in case of problems.

Edit.....This is much LESS a problem when the plant is small......but becomes an ENOURMOUS problem later....when the plant is huge and flowering and you've invested a lot of time and energy by that point and you really do have something to lose if the plant takes a dive.

The big thing about hydro imo......it must be maintained at least daily unles you have many $$ and can put everything on automatic timers etc. If you miss a day and something goes wrong......depending on what the problem is........it could be enough to kill your plant.

What this year long thread is trying to say: Every bit you can do to help keep a system more stable helps.