I have used it in the past, but that was a while ago and was not for long maybe a month and had to move the tank and was never used again. I found the unit which is a Red Sea 100 with controler but needs a ORP probe and I was wondering if it is worth buying a new probe. I have seen so many nice tanks that run Ozone. I know it keeps the water sparkling clear and you don't have to use much Ozone to achieve that. i know it's like anything else so swear at it and some swear by it and would never run a tank without it.