SWCC, I am interested in UV for its potential impact on decreasing pathogens. Certainly a complex topic. I owned an elementary unit back in the mid 1980s and thought the data was scant regarding their use. However, theoretically the units now seem capable of some batericidal activity especially with other modes of filtration. You have expressed positive opinions on this topic and I would be interested in your analysis of the data (both published and empirical). I am considering a unit for my 525gal tank to reduce my pathogenic burden. Thanks for your help.