Please help ID this. Algae?

[jgraz]

I just noticed this.....Algae?(see pics) Showing up only on one side of my tank and more or less near the bottom. Yesterday I also noticed that the sun was shining through my skylights right onto the area. It is smooth to the touch, not slimey, and does not come off the rock easily when brushed or blown off. Definatly not diatoms or Dino's. Though I have not yet ruled out Cyano. And it does not have any flow to if that makes sense. The flow in that area of the tank is good, as it should be, I have a MP-10 in a 20H, set to reef-crest. The pump maxes out almost all the way during its high point. Any help on the ID would be great. Someone in another forum mentioned the possbility of it being sponges.
My Parameters are: Ammonia/Nitrites/Nitrates=0
Phosphates=.04 Hanna checker- I expect this is masked by the algea
Calcium=440
Alkalinity=8(at lights out)
PH=8.2(at lights out)
Here are the pics

 

[brunkdent]

wow! I have something in my tank that looks very similar to that just lighter in color...there is actually a feather duster partially underneath the stuff that I've got. Its still healthy so whatever it is doesn't seem to be harming anything. I would be interested to know what the heck it is though!!

 

[Flreefer]

I also have small patches of the same color algea in my tank, one or two have been there for years. I don't think it is detrimental to the tank, other than maybe aesthetics. I've heard them referred to as stains, although IMO, it must be some form of corraline algea. At first I thought it was Cyano also, but it doesn't come off. I would also like to learn what this stuff is!

 

[brunkdent]

well I did some research and then really examined the rock this stuff was growing on and the stuff in my tank is most definately a sponge of some sort...I'm not sure of the exact species though. Mine started out looking the way yours does in the picture and we thought maybe a snail got squished but yesterday I could see little pores and its gotten much bigger. Just keep watching it esp. if you have any corals I would try to keep it away from those. Otherwise I don't see it causing any harm to anything in the tank. If anything its a help. I'm no expert, just did a lot of research. I will keep looking to see what kind of sponge it is, my guess is as good as anybody's really.

 

[jgraz]

well I did some research and then really examined the rock this stuff was growing on and the stuff in my tank is most definately a sponge of some sort...I'm not sure of the exact species though. Mine started out looking the way yours does in the picture and we thought maybe a snail got squished but yesterday I could see little pores and its gotten much bigger. Just keep watching it esp. if you have any corals I would try to keep it away from those. Otherwise I don't see it causing any harm to anything in the tank. If anything its a help. I'm no expert, just did a lot of research. I will keep looking to see what kind of sponge it is, my guess is as good as anybody's really.

Can you get me a pic of yours. Mine has pretty much stopped or slowed growth. With a bit less feeding. It's still there though. Still in the same form. Tight to the rock. All on one side of the tank and everywhere light is not as intense. This is all dead rock from reef rocks. On the lighted areas it's clearly greenish in color from algae growth. But these areas are brownish.

 

[brunkdent]

I can get you a pic later today..mine is facing straight up at the light, I just re-did my rock scape and in this position is where I noticed the growth take off, so maybe more light?? mine was a brownish purple...now its more white purple..