My water was clear three days ago but a slight brown/tea color. Then it turned so dark that I can't see the bottom 6" of the pond. I had a barley bag in the filter fall and took that out as I was told that might turn the water brown but what else could be causing this? It's not cloudy and no "gunk" in it, just dark in color. I did add an aerator this past weekend and I see less algae on my rocks and liner - could that have something to do with it? Thanks in advance!