Green or golden brown algae, or both!

[Randy Holmes-Farley Verified Community Expert]

Curiously, I have noticed that the color of the growth on the inside of my glass depends on position. Green in some places, golden brown in others.

The pictures below show places I did not scrape yesterday since there were snails there. I’m not sure if the effects are water motion driven, or light, or both.

If I had to guess, I’d say there is more light and more flow on the golden brown areas.

Both pictures below are from the side panel
looking down the length at the inside of the glass. Two big patches (bottom picture) nearer to the side panel have brown on top. The further, smaller patches (top picture) have green up top, nearer the water line.

Have others noticed this dichotomy?

 

[Red_Beard]

Indeed I have. That selfsame phenomenon occurs on my glass as well. I have observed it to be a function of algal density as well, with the yellow brown occuring after having been a dusty green not long prior to the more dense coating of yellow and transitioning once again after a period of time to a more brownish tint while also becoming a more dense, less opaque film. I think light and flow would definitely play into that equation, creating the more favorable conditions to spur additional growth at a more rapid pace in some areas.