I was gonna ask the same question, Dave. Do you, the members of this forum, use an ultraviolet light? I am currently using a Savio biofilter with a 150 gallon Skippy filter and my water is still murky. I'm trying to be patient, but I'm not sure if it's in my personality. Dave, I did use a Aquascapes UV light for my old 1000 gallon pond and it worked great, but it's too small for my new 4000 gallon one....go figure. I'm looking forward to reading everyone's replies.I have read that if you have a "balanced" ecosystem, your pond will be clear...obviously, in my case, there isn't anything balanced in mine...lol