Purple Rocks?

i've seen many tanks with purple rocks so my question is do they get like that over time or is that some special rock you have to buy

 

Coralline algae comes in many colors. The colors that tend to do best under reef tank lighting are purple and pink so those tend to dominate well established reef tanks.

 

so what your saying is it's some type of algae
Correct?

 

It's very special secret rock. I can sell you some, but it aint cheap.

Just kidding.

It's coralline algae. As long as your parameters are good (good dKH, Calcium, and Magnesium), and you have sufficient lighting, it will eventually grow. Once it gets on the glass, you'll start remembering (fondly) the days long ago when you didn't have to scrape the glass.

 

I doooo remember........

 

You have to have some somewhere for it to spread. As the tank matures it will grow on everything.

 

If there is surface it will grow. period. (assuming there is some there to start)
My coralline grows anywhere and everywhere. It seems to need minimal light nor flow. The stuff even grows on my snails and h. crabs!

 

Very funny. Give it time seed the tank keep your params good and you'll be wishing it would slow down.

 

I see we what we have here is one of them thar biz-nus type guys.8)

 

When you start to scrap it off the rocks that piece you just scrapped will find a new home and start to grow there!