Steve Pushak wrote: -SNIP- >>> I suppose treatment with a UV sterilizing filter -might- be a possibility. That's not very practical for most of us. <<< -SNIP- Has anyone ever tried UV sterilization to eliminate the surface scum bacteria? Is any one willing to try? Cheers, Mark ------ pearlsco at u_washington.edu How much does a fish need a bicycle like a man needs... ?