I got a 9watts uv for my pond and my water still look green. When I get a cup of pond water it lite tan tea color and when I left it there for a day it clear out with nothing settle to the bottom of cup, maybe tiny little white stuff. Is it dead algae or something? Is 9watts uv strong enough for a 1300 gallon pond? If not is it ok to get another 9watts and run two 9watts or get a 18watts?