Last spring I had made the mistake of using regular garden variety of potting mix to pot my water lilies. Right away the water took on a tea color that I had trouble getting rid of. I think it was DrDave, Koiguy, Koikeeper, and a few others that help me correct the problem. I didn't change the potting soil until last week, but I think doing several water changes over a four week period made all of the difference. In addition to installing a UV Clearifier, the pond water gradually became crystal clear. The fish seem to be healthy and happy, and so am I.
Later, I ended up adding a 27 gallon boi-filter behind the water fall that really made a difference in how often I had to rinse my skimmer/pre-filter.
Happy ponding,
Rich