Ebb n Gro Timer questions. Rockwool cubes wit Hydroton

Second week flowering and roots are starting to breakthru. I've been watering twice a day. One shows signs of drooping but other are fine. Is this enough water or too much? Also should the cubes, which are not really rockwool but Atari roxx, be placed where the top is about a half inch above hydroton or totally covered up by them. Lemme kno... thanks

I'd water 3 to 4 times a day with the rockwool tops slightly covered with hydroton.