Was it slimy and soft? Coraline is basically a coating of calcum. It would only 'scrub' off with something really abrasive like sand paper, or it will 'chip off' into tiny gritty pieces which feel like your substrate sand.

it wasnt slimy but it was soft

If it was soft and yet you're sure it wasn't cyano, you may have scrubbed off a sponge. I have and organge sponge that grows as a thin sheet, but once again, sponges don't like a lot of light so I find them on the undersides of rocks. Coraline of any colour is hard and any coraline bits you scrub off, will sink rather than waft around in the water.

I guess time is the only way to tell. If it was indeed cyano, it will come back pretty fast if you haven't changed your routine in any way. If it was coraline and you scrubbed it off while inside the tank, you may have helped it spread. :) If it was a sponge, it may never come back.

If it was teh same as my pic, then its not cyano. Cyano does not like flow, it can be blasted with a turkey baster. This stuff is growing right underneath one of my returns in the highest flow area of the tank. I'm guessing its coralline, but its jws444 says it prefers darker areas, but mine is growing on the tops of all my rock, that pic is one of my rocks closest to the surface. Now I don't have my MH's yet....just PC's so it may receed once my MH's go up in a couple of weeks.

Hey, that's the same stuff I've been wondering about lately as well, and it fits your description to a T. At first I thought, "burgundy coraline?" But it does have a slightly velvety texture, but I can't scrape it off with a fingernail.

I'm hoping its cyclical - some of it seems to be receding, and its only on one or two rocks at one end of the tank... :confused:

It is almost like a thin plating sort of cyano??

I would really like to know if this is common or not - anyone else have this stuff?

Maybe if this was moved to the Reef forum?

i have the same stuff, i always assumed it was coraline.

Have a look at an encrusting sponge - Monanchora barbadensis

http://www.wetwebmedia.com/spongesiii.htm

4th pic from the bottom.

I guess we'll have to look really close at the red formations on our rocks. I see the sponges definately having an 'organised' system of canals. I definately don't recall seeing mini siphons on mine.

No man, not sponges ("we don't need no stinking sponges"). :mrgreen:

I guess it must be a type of coraline, then. Just seems a little different, almost velvety as mentioned. And a little more opportunistic maybe.

yeah i dont thinks so either. because its smooth with a velvet look