Hi Greg, that ozone generator specs claim 200mg/h, might be a little generous, but more than enough for 250+ gallons.
Ran it on the 180g tank that had a total volume of 270g and once the ORP was in the comfortable range the generator on ran a couple times an hour for 5 maybe 10 mins. It will really depend on the load and the delivery method. A tall reaction chamber works best for longer contact time, but into a good skimmer works very effectively.
