I ran an aero system that was pretty much as complex as it gets. I like beneficial bacteria and would not recommend a UV Sterilizer. I also would not use any hydrogen peroxide for the same reason. If you have a chiller and keep the temp at around 66-69 degrees, I think all of the problems of root rot will be kept in check. I had so much "flow" in my res that i didn't use beneficials or anything and the water temp ran about 73. Pretty amazing i didn't have problems but if you keep that water moving like a river, it will stay pretty healthy.

As for the cycle times: I used 1 minute on, 6 minutes off. The best reason for the off time is pump life. Most pumps will heat up under a load (pressure from the system) and heat shortens the life of them. Depending on how well the system sprays, it can be anywhere from 4 minutes off, to 15 minutes off without much trouble.