A CD ozonator eventually requires maintenance. The Marquis ozonator has a purple glow to it that lets you know that it is on, it is either working 100% or it is not working at all, never any maintenance. I doubt it is a cheaper unit, Marquis has never been known to use an inferior component in order to cut costs. As DPS said in an earlier post, when an ozonator goes out, the customer usually notices it because their water chemistry turns to crap.