I have a kidney shaped 6 ac. pond that is 30' deep at one end and 0's at the other . I built it in the 80's and it's been doing great , but the past several years I've been getting a rust colored bloom mostly in early summer when I get direct sun on the water surface . It seems to lay in long waves just below the surface and gets really thick so as to turn the water red . It also seems to be in about 1/3 of the pond area and it seems to be increasing every year both in length of time and area covered . I wonder if it's Serratia or perhaps even an Iron Bacteria as we have lots of Iron in this area . Is there anyway of identifying what this is ? Also is it a danger to my dogs health as he both drinks and swims there daily ? Thanks Orville