Pond Boss Forums INTRO Questions & Observations What is up with this?

I doubt it is a precipitate. Usually precipitates settle and do not float. Most offensive or nuisance bluegreen films look like that with various colors of green to bluegreen as that above. Some green algae species will form similar surface films but never that bluegreen color. Sometimes they can be 'up' and 'down' in the water column depending on time of day and species of algae. They can surface & disappear quickly or hang around for weeks. Most often, when they have the noticeable bluegreen color as that above, the stuff is in late stages of development or decay which is maybe why it quickly sank or wave action broke it up and then it sank. Numerous variables possible. If it returns and you really want to know what it is, send me a Private Message and I will tell you how to send me a sample of it. Bob Lusk calls me a microbiologist but actually I am an algal taxonomist - one who identifies algae. taxonomist - a biologist who specializes in the classification of organisms into groups on the basis of their structure, origin and behavior