<< Worked like a charm. At least 1 years worth of stuff in those tubes. A sight to behold. Arthur >> Didn't that gunk ever come flying out the outflow tube when you restart your filter? That's how I tell it's time to clean the tubing -- upon startup there is a cloud of "gunk flakes" that come flying out -- I wish I could train the fish to eat that stuff, but they are too spoiled. :o) Catherine