I've had one for a couple of years, had a club meeting at my home to show it off. It's reduced the frequency of diatom scrubbing off my tank glass big time. But don't abandon other methods of nitrate/phosphate reduction as well. And while some people say you don't need to skim with an ATS... I still skim. . While my skimmate may not be quite as grungy with the ATS going, it's still pulling off some waste. It is recommended that you harvest and rinse the ATS weekly... I agree. (search my previous posts for pics)