Absolutely white empty shell, and white stuff on rock...

[zeromus-x]

I don't know how to explain this one well. There's a piece of live rock near the front of my tank. It's got this very white coating on it... I don't know what it is, I haven't tried touching it or anything. Today when I got home from work, I discovered a shell sitting next to it... as white as white can be. Almost looks like what you'd imagine a shell to look like if it could molt its skin. Very bright almost blueish white. Crazy looking. I took a picture with my camera phone in hopes that it'd come out decent, maybe you can kinda tell.
Any ideas here??

 

[bigarn]

The white on the rock could be an encrusting sponge.... just a guess. I really don't know about the shell. :thinking:

 

[zeromus-x]

I've only got the stock light on there.. 15W maybe? It'd be one unhappy sponge! Here's a picture of the shell.
The red is just from my camera

 

[bigarn]

Sponges don't require alot of light.... I'm sticking with it.

 

[nitram]

how long have you noticed this. was it just oneday it was there or been growing for a while?

 

[zeromus-x]

The white on the rock has been there for at least a week; the rock had been in the back of the tank, I didn't notice it. I moved it up to the front with a net to take a closer look.
The shell wasn't there when I left for work this morning, I know that.

 

[darthmatt]

it kind of looks like my live rock when it was dying from not enough light. All the coraline was bleaching out.

 

[zeromus-x]

That could be possible but it's only white on the side directly facing the light. It's at the bottom of the tank with all the other LR (I've only got about ten pounds of it).

 

[timo]

Bleached coralline.

 

[cbort]

i have bought a couple rocks like that from my LFS, one was actually the same stuff except orange, and the other is white. Are you sure you didn't buy it that way. i don't know exactly how long it takes for sponges to grow, but surely that can't grow as fast as algae??

 

[zeromus-x]

Originally posted by TimO
Bleached coralline.
I've never had any kind of coral, especially not one that would cover the whole side of a piece of rock. I want to take it out and look at it but if it's something growing on it and it's not harmful, I don't want to kill it. Ugh.

 

[timo]

Did those areas ever have any color...what was it before the white... if it changed, it changed from something...were you there when it was bought/placed in the tank...
Coralline as a word does not imply the presence of a coral. It is one of thousands of red algaes, this one forms its body from calcium instead of the fleshy algae we all know and love. Typically it's purple or a varient thereof. Under low light situations (your tank) it dies, as plant-like creatures will do, and leaves it's calcium skeleton (your picture) as a reminder that you paid too much money for rock you just bleached.

 

[zeromus-x]

It was with a batch of rock I got for about $3 a pound on sale at a local fish store that was getting rid of a lot of it. As a result, if it's bleached, it's not like it's a huge loss. It's been in the tank maybe a month and was white-ish to begin with (not white, but not like Fiji or Tonga or anything). I've had other rock in the tank for at least a year and have never seen anything like this happen. If it's bleached, should I take it out? Or maybe I should just bury that part of the rock in the sand?
I thought a FOWLR tank didn't have really high lighting requirements unless you actually wanted corals/anemones.

 

[timo]

Bleached rock is not a danger to your tank.
Although not regarded as a "high light tank", having live rock itself has sort of a tacit implication of at least it's requirements, and while I haven't the foggiest on the needs of coralline, at least now I know it's greater than 15 watts.

 

[timo]

By the way, if you could have placed that rock under good lights, that would have been a steal.

 

[zeromus-x]

The rest of the rock appears to be doing great, along with my Fiji rock, and the other sides of that one. It was a great deal, and I wish I had more money to stock the rest of the tank.
Glad I could be a learning experience for you. I believe it's 15W. It's the stock fixture for a 36g bowfront corner All-Glass tank. I'll upgrade the lighting when I can afford to pay my power bill!!

 

[dedwards]

All of my live rock went through this phase. Mine have colored up quite nicely with proper lighting. I moved a piece a few weeks ago and the underside is now visible and looked a lot like your pic. I'm going with bleached coraline.