as a general rule of the thumb, maintaining ur ozone levels thereabouts 380mV will be considered the best range according to a thread in RC from JBNY (do a search in RC, u shld be able to find the relevant thread, me 2 lazy to search).
u raised ur orp by abt 250mV in 4 hrs??? that's too fast. ur fishes might not be able to take it. too drastic a change in orp parameter might cause gill infections and organs dysfunction. 0.5mg/hr of ozone per gallon of water will be a rough guide to follow.
HTH