If you are using any legitimate type of aeroponics system, you want the water to be circulating all the time. Any break in the sprayers means that they aren't getting what they could. There is plenty of available oxygen to the roots in an aero system, which is the purpose of turning off the water pumps in some hydro setups. I would say that you could buy the timer, seems cheap enough, but you will be taking away from the whole point fo aeroponics.
