When clones first go into that type of system you only need to flood a couple times a day. Say, once when the light first comes on and once 8 hours later. You don't want to overwater them at this point because you want them to seek out water, thus spread their roots. If you use fertilizer, go low ppm - 200 or so.
Once you see roots coming out of most of the pots, you can turn up the PPM, but not before. If you turn your PPM up too soon, some of the plants will take off immediately and some later. You will end up with wildly different sized plants which can be a bitch to manage. If most or all have dropped roots before you turn up the PPM, you will have nice ever growth which makes it very easy to care for down the road and helps your yield too. High yield comes when you have nice even growth and a good average yield per site, rather than a few really big yielding plants, and a bunch of smaller ones.
Hope that helps.