mystery growth

Hi folks- just learned how to post and attach a pic (I'm a little slow with this stuff). This brown stuff has been around for a couple months. At least that's when I noticed it. It doesn't seem to get bigger or smaller. It's almost like the rock is stained. I just added a third kissel 150 over the area and I'm not sure if it will take off. I haven't noticed any anywhere else. Parameters are all good: calc-450, nitrates 5-8 range, phosphates .03, alk 10. I have a 40 gal w/skimmer. Good flow. No diatoms and little algae. I think my tuxedo urchin may have died after eating some. Thanks in advance for any help. I have also considered taking the rock out and nuking it but I'm not sure what to use.

 

Hard to tell from the picture, but it could be dinoflagellates.

If it is brown, generally diatoms. If it is brown and bubbly, generally dinoflagellates.

 

Looks like some sort of padina species to me. It will only come off with manual removal because it sort of encrusts on the rock.

 

Appears to be cyanobacteria to me.

 

That is what I was thinking too. Can you siphon it off?

 

Thanks for the input. My first thought after reading a post was dinoflangellates. I am a little skeptical on that because dinos seem to usually start in the sand bed and grow so fast. This is either dormant or dead and is near top. But now that I have put more light on the area, I'm watching for any changes. I haven't tried to siphon it yet. My limited experience with cyano is that cyano is more jelly-like. This is closer to a fuzzy stain that hasn't changed for months. It could have come in on the LR as former infection that left a stain, but I've seen how fast these things can get out of control. I'm on day two of increased light. I'll keep you all posted. Thanks again for taking an interest.

 

NOT dinoflagellates

 

Hey pickupman- I'm thinking the same, but I'm wondering why you don't think it's dinos? For an update, since adding light to the area yesterday, there have been no changes it the patch but I've got my eye on it.

 

Dinos will be stringy. Almost like brown snot. Bubbles all over.