I would just like to add to this thread, as I'm currently running a test with cloning in hydroton flood and drain or ebb and flow.
I have a 14 gallon tote as the reservoir and a 10 gallon tote as the grow bed. Floods for 15 minutes and off for 45 minutes, all day, under 24 hour T5 grow lighting. The grow bed is about 8 inches deep and only filled with 5 inches of hydroton and only floods up to 4 inches so the top of the hydroton stays fairly dry to keep alge from growing. A humidity dome from another cloner fits pretty well over the hydroton cloner.
Since this little cloner was and is originally intended to start converting my veg/mom room over to aquaponics, I did not use any root hormone on my current cuttings. I am just using tap water(ph 7.1) with some maxicrop(liquid seaweed), and will eventually add some ammonia to start the nitrogen cycle. I would like to lower the ph a little, but I think it will be fine for now... we'll see.
We'll see how fast roots develop, took the cuttings on 11/2/12. Will report back when roots pop. The cutting so far are loving the hydoton flood and drain, no wilting at all at day 1, 2 or 3 and I haven't needed to spray water on them at all. Looks like this is going to work out very well, and if it does, this may become my main method for taking cuttings once my main aquaponic system is up and running.