Getting hit with heavy rains today, but will take better pics again tomorrow once it returns. Pretty sure it's algae because it's bubbling green at spots. It starts out as clear film after rainfall, then turns to gray, then bright green as temps rise and if little wind. I've attached pond results, hardness is 174 mg/L. Had a fish kill the weekend we moved in last year before I could get aerators in and do get lots of large sycamore leaves so thinking that could be source of phosphorus. I don't treat my property at all and don't believe my neighbors do either. Thanks Journeyman and Mfitzs70!
