Thin, transparent film coating macro algae.

[burtpark]

I have caulerpa-like macroalgae in my tank with a thin, transparent film covering them. They're not caulerpa, but similar. Is this normal? Didn't notice it before. I thought maybe it's due to the waterflow, but it's even covering those that are being blown by the powerhead. It wasn't there before, just noticed it now. Thanks

 

[tangir1]

Any pic?