i use ozone in much higher quanitys in hydroponics. i have generators/corona plates that put off anywher from 1000mg/h to 7000mg an hr. im willing to bet the ones used in reefing are nowhere close to those doseage. ive been in rooms of a 1000mg/hr for increments of 20mins at a time with no bad effects. i forgot to turn off one of the big rooms with the 7000mg/hr corona plates for about 45 mins an hr and only got a headache. what im getting at im exposed to ozone almost everyday. smells quite fresh actually. so im shure the amount used in aquaria cant be dangerous to us. the tank on the otherhand detremental. so i will read all articles and a verry big thank you to you for the links.