If by dark you mean that it looks like tea, then it is probably tannins.
They can be removed by the use of filter charcoal or massive water changes.
The source is usually a tree nearby that has high tannins in the leaves.
--
RichToyBox
http://www.geocities.com/richtoybox/pondintro.html


"G-Hoch" wrote in message
om...
Hello all, I have a 50 gallon pond with 2 goldfish here in North
Texas, and for some reason the water is very dark and cloudy, there
doesn't seem to be a lot of algae, but I don't ever remember seeing
this before.

Thanks,
Gary