white algae spots

[ystop]

my tank is at least 6 months old all readings are ideal to ok
but now there are white algae spots on the back of the tank
we "scrape" and clean the 3 sides and let the back just go
the algae has always been green or a beautiful purple, but now there are white spots
are they bad?
thanks for your help
i do have pics but they are too big, any suggestions on how to make them small enough to post would be greatly appreciated

[romunov]

Use program called "IrfanView". It knows how to resize, even in batches!

About white spots. Could it be coralline algae be bleeching or something?

[rshimek]

Hi,

I would have to see the images. However, small - dot or circle white - spots are often a sign of reproduction in coralline algae. Such spots are the reproductive structures (gametangia). Larger patches are due to algal death, and this can be caused by many things.