Tea-Brown colored Water in Pond
We have a 8,000 to 13,000 gallon pond. Upper Pond, stream,and lower pond. It is now 4 years old. Pond enclosed in liner, with rocks on the bottom. We have many plants that provide oxygen and protection for the KOI.
Problem in the upper pond is that the color is tea brown. The water is not dirty. It has been like this for the past couple months. All tests are great except the PH is high. We have had NO green algae this year, which could be due to the high PH. I have heard that a little green algae would be good, which will probably eliminate the brown tea color. I have tried the activated charcoal and matting, but it did not make a difference. Fish appear to be acting normal. We have a pump in the lower pond which circulates the water to the upper pond, into a natural BIO filter (rocks and plants). The BIO filter dumps into the upper pond via the waterfall. The BIO filter is dirty - I will be cleaning it out this week. Any thoughts guys?