Live Rock Question

[jmorgret]

Had my tank up and running for about a month with cured rock from a LFS. Everything was fine for the month. Added small cleaning crew this past weekend, and noticed today some of my rock is starting to turn white. Is this normal?

[Big Amish]

If the white sections were once covered in coraline algae, then it sounds like the coraline might be dying off. How much light do you have on your tank?

[jmorgret]

It's just the regular light that came with the tank, goes on in the morning and off at night. That particular piece didn't seem to have any coraline on it that I saw, although I do have one piece in another part of the tank that is covered with it and is still purple. The tank is a FOWLR, so I did not upgrade the lights. The rock was fine for the month it was in there with the current lights, for what it's worth. Should I be concerned?

[Big Amish]

Well, first off I should state that I don't consider myself an expert, though I've been reading and talking to a lot of people during my short time in this hobby. I haven't heard of any cleanup crew animals that would turn your rock white ( Unless it was a white rock that was just dirty. :) ). However, I do know that dead coraline algae will turn white, thus my initial question.

I would just keep an eye on it for now. Watch areas of high coraline growth for changes. Also watch the white areas to see how they spread, if they continue to. By the way, what was in your cleanup crew?

Cheers

[mikeatjac]

It sounds like the lights you have is not strong enough to support coraline. Most lights that come with tanks are for FO.

[jmorgret]

Hmm...ok, then I guess my next question is: is this bad for my tank? The die-off I mean. I suppose I'm just confused as to why the algae would start to die off after a month under the lighting. What happens to those white area of rock, do they get some other growth there eventually? Because it doesn't look all that great.

[Blown 346]

The rock will eventully start to get its color back slowly after a few months.

[boxfishpooalot]

the part thats white means your rock is internally cleaning itself. Bacterial tugor(pressure) is pushing out dirt and bringing in waste for them to eat.

This is a good thing :)

[WaterKeeper]

Probably part of the coralline was injured in transport. As coralline has a calcareous cell construction it leave behind a white structure when it dies. You might consider adding a combination of a normal output daylight fluorescent and an N.O. actinic to the tank. You don't need bright lighting for coralline but having the light in the correct spectral range will do wonders for it.

Tugor huh. Now there is a throbbing explanation of decomposition. :D

[jmorgret]

Interesting. FWIW, here is a pic I took today, not a very good one tho as my camera is not so good on close up shots

http://reefcentral.com/gallery/data/500/46802white1.jpg

I'm not up to speed on lighting as I thought with a FOWLR it was one area I didn't really need to get into, so excuse my ignorance, the NO actinic...is this a type of bulb or do I need a new lighting rig?

[mikeatjac]

Look at the bulb and tell us what it says. Probably a light for a FO tank. Most NO bulbs florescent at 18 watts and not enough to support coral or coraline. However for a fish only tank it does all you need it to do.

[jmorgret]

All it says is Aqua Glow, 24" and 20 watts. Made in Japan.

[jmorgret]

Is this bulb good enough or should I get a different one??

[WaterKeeper]

That is a little hard to say without knowing anything more about your tank. If it is a small tank I'd suggest getting another light strip or a two lamp hood and using one actinic in the mix. My thoughts are that the current tube will probably support some coralline growth but no make it flourish. Also an actinic will make your fish stand out more.

[jmorgret]

The tank is small, 30g with a 20g sump. I saw some lights fixtures on Foster and Smith that have 2 bulbs in them, should I get one of those and keep my existing bulb and add a actinic? Then do you run them together at the same time? Thanks for the help Waterkeeper! Is that dead/dying coraline you see in my picture then? And if so, is this gonna over run my rocks and make them all white, which would kind of suck.

[WaterKeeper]

For your fish only I'd say either getting a two bulb hood or adding an actinic strip light would do. Whichever pleases you or fits your budget. Many people run all the lighting for about 10 hours per day and just the actinic for an hour in the morning and again in the evening to simulate dawn and dusk. It is not imperative to do this however.

With the additional lighting those white areas will be again covered with normal coralline.