Ozonizer Recommendations Please

[TheReefGeek]

You can get those Enaly ones on Ebay for $50 (200mg/hr)

Anyone tried using multiple ozonizers on one tank? Like if I hooked up 1 of these cheap 200mg/hr ones, then I upgrade tanks later, could I just add another 200mg/hr unit on? My thought would be that one controller might be more sensative than the other, so one unit stays on all the time while the other just occasionally. Would this be a bad thing though?