I've had a build up of this algae (maybe) over the last 4-6 months. Under white light it's brownish/red. I broke a piece of coralline algae that was plating and put under the microscope. It's difficult to scrub. It can be scraped off live rock, but not easily. It almost has an onionskin like quality when pulled apart (you can see in the pics). I will apologize now for the pics, it's harder than you'd think to get an iphone shot through a microscope. I needed another hand 
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This is 1x mag of piece of coralline. Bottom side where it's lighter is where the coralline broke off, top side has coralline intact under the algae.
image by Peter Young, on Flickr
2x mag of the same shot.
image by Peter Young, on Flickr
Similar shot of another piece.
image by Peter Young, on Flickr
1x shot of it with no coralline underneath.
image by Peter Young, on Flickr
2x mag of the same shot.
image by Peter Young, on Flickr
Again, this stuff is pretty weird to me. Snails will clear it, but can't tell if they actually are eating it or just dozing it. I originally thought it was some super dark coralline, because under blue lighting it looks dark purple or even black and had similar growth pattern. I keep my nutrients somewhat elevated (not zero) with PO4 around 0.05-0.1 and NO3 from 5-15 ish. No other algae issues. Any ID ideas would be appreciated.
.This is 1x mag of piece of coralline. Bottom side where it's lighter is where the coralline broke off, top side has coralline intact under the algae.
image by Peter Young, on Flickr2x mag of the same shot.
image by Peter Young, on FlickrSimilar shot of another piece.
image by Peter Young, on Flickr1x shot of it with no coralline underneath.
image by Peter Young, on Flickr2x mag of the same shot.
image by Peter Young, on FlickrAgain, this stuff is pretty weird to me. Snails will clear it, but can't tell if they actually are eating it or just dozing it. I originally thought it was some super dark coralline, because under blue lighting it looks dark purple or even black and had similar growth pattern. I keep my nutrients somewhat elevated (not zero) with PO4 around 0.05-0.1 and NO3 from 5-15 ish. No other algae issues. Any ID ideas would be appreciated.
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