What is this stuff?

[Lithy]

I have had a red sponge-looking thing grow on one of my ricks for a while. In the last couple months if starting growing like crazy and spreading almost an inch a day.
Originally I was not worried and in fact I think it's attractive and I like. But now I am worried because it is out of control and I would like to know more about it. Alos a new patch has appeared in a new spot in the tank away from the original colony.

What is this? Is it bad for the tank?If needed, how do I remove it?

Thanks!


<a href="http://picasaweb.google.com/ale.rugge/ClamGrowthsAndRedSponge/photo#5118844021223693090"><img src="http://lh5.google.com/ale.rugge/RwnJhDmrmyI/AAAAAAAAAGo/4kzSUjQwfhM/s144/IMGP4117.JPG" /></a>
<a href="http://picasaweb.google.com/ale.rugge/ClamGrowthsAndRedSponge/photo#5118843982568987394"><img src="http://lh4.google.com/ale.rugge/RwnJezmrmwI/AAAAAAAAAGY/cs_inux-5zU/s144/IMGP4123.JPG" /></a>

 

[boxfishpooalot]

Looks like cyanobacteria, evil algae that will spread all over your sand, rocks ect as you already are noticing.

Ime its caused by high levels of organics. I noticed your sandbed has some brown spots. Possibly detritus(fish poo)

Or your using tap water. It needs phospahtes to grow.

 

[Lithy]

A few moths ago I struggled with cyanobacteria. This was brown slimey stuff and grew on the LS only. An extra powerhead and a sand sifter cured this issue completely and in fact the sand is nice and white.
However, I have had more algae growth in the last 2 weeks, especially a bright green fast-growing film on the glass wall. I do suspect phosphates, although my test kit reads zero (I do not always trust it). In addition the macroalgae in my fuge was not doing well and a lot of it died, I suspect due to low light. With respect to organics, the skimmers works like mad and the nitrogen tests are at zero.
This weekend I increased the light in the refugium and replaced the phosphate-removing sponge pad in the sump, downstream of the fuge with macroalgae. I hope these remedies help controlling the red stuff as well.


Sounds like a good plan?