I just make sure the soil is moist, you can't really measure it because it all depends on the container size and size of the plant. I'm a firm believer in letting the soil dry out some between waterings so the plants have time to absorb oxygen in between waters, that is the whole point of hydro, getting an even mixture of water and oxygen. If the plant gets too dry it will tell you by wilting, in which case you water and the plant goes back to normal, usually within 15 minutes. Your brain wants you to water about 3 times a day but is best to have it dry out between waterings so the plant can get the oxygen it needs to the roots, if you water too much it never gets the opportunity because the roots are always in water. Just think of normal house plants, how often do you water them ? How often have you forgot and the plants still live after 2 - 3 weeks of not watering them. When they say most people starting out have problems due to overwatering, they aren't kidding, because once a week of watering is usually good enough, twice a week also works once you get the hang of watering. Like I said I recomend once a week for beginners unless the plants wilt in between in which case you do twice a week.Give it a try and you won't be disappointed. Seedling may need the two or three times a week due to small containers and heat from the lights, is about the only exception.
SPROUT DOWN.
