I have a problem that I hope someone can help me with. My pond has been reasonably clear with a hint of brown, until yesterday. When I went out there, I couldn't see anything in my pond except black muck. Some of my plants, such as irises have fallen branches lying on the water, and you can tell that they are blackened with this stuff It rinses off when you swish them around. I tested my water today, and everything seems to be ok, with PH up just a little. I'm very new to this and don't know if it's some type of algae or what. My pond is approx. 800 gal. with a 4200 gph submersible pump in the skimmer, with a 35 gal barrel filter holding sponges and scrubbers. My water looks clear coming out of the filter, but the pond looks terrible. Please help! Thanks :neutral: