I need to revisit this thread with a question pertaining to my BG pond. Up until the last week or two, my BG pond, aside from tea brown water, was looking good. Secchi disc readings were dropping from 3.5 feet to about 20" now. Surface temp 80 degrees, water pH around 8. Summer temps have moved in with 80+ degrees being the norm mixed with a few days in the low/mid 90s last week.

The intermittent stream that feeds this pond is now dry. Current water levels are 2-3" below my stone dam which was built across the outlet of this small 0.12 acre puddle. We had a brief rainstorm this past weekend, which was the transistion front from the 90s last week to the more seasonal temps now.

In addition to the main topic of this thread, a green film that covers the pond, there is also a film of goo that I can only describe as looking like liquid driveway sealer. This stuff only resides on the surface and is easily dispersed when the aerator kicks on. A sample jar of water, taken from arms length below the surface 4 days ago, is clear. The watershed on the east side of this pond consists of tall grass with trees (nature's piece) while the west side is lawn. No chemicals used, I just mow it on a weekly basis.

My question pertains to this black goo and what is it? Cody above mentions algae films. Could this be the result once the green algae dies off? Other than being a visual nuisance, I don't think the fish are being affected. I'm sure it would be no problem to skim this stuff off using BZ's prickly rope.

Thanks in advance for all replies.