Growth on live rock

Ive had this nice big piece of live rock in my tank for a while. It has a brown color to it now. The newer stuff in there I got from the same place. I remember the bigger piece before it turned brown having those little purple spots just like my newer rocks do. Is the brown color normal or some type of algae i need to get rid of?

 

Looks like you had a diatom bloom. Normal in a new tank. It will get cleaned off by the cleaning crew. Don't worry about it. You can opt to scrub your rocks in RO water mixed to the SG of your tank. I did that with my first tank. I let my second tank go and the turbo snails made quick work of it.

 

What do you have for lights first of all?
The new rock has coralline algae(pink coloration) that is provided by having the right amount of light, water flow and calcium!
Both pieces of live rock provide beneficial bacteria and organisms living within and on the surface of the rock so don't be displeased with the discolor of the old rock! Coralline algae will reappear under the right conditions!
A product called "Purple Up" can assist you and promoting the coralline algae that many of us desire!

 

Thanks for the tip. Im pretty new to all this, a week ago i did'nt know squat. I have a simple flourescent bulb. I think its like 15 watts. Which i know now is pretty much worthless. I ordered these yeterday: Aquarium Lightings - Power Compact Lighting - Free Gift with Light Fixture Purchase

 

That is the main reason for the loss of your coralline algae growth on the rock. Your light intensity doesn't support coralline growth.
That will make a difference for you and what you plan on purchasing down the road!
Good luck...
Any questions, feel free to ask away with all the knowldegeable aquarists aquarists here at 3reef!

 

Thanks ive gotten a lot of help here from a couple of guys im glad i didnt listen to anybody at my lfs and came here first.

 

You wouldn't believe how much negative feedback and mis-information that is given by local pet shop employees!
In my opinion, unless you have a good repore with the pet shop/employee, I would refuse to just take their word for it and get a second opinion. Many pet shop employees work in the fish, dog, bird and reptile sections throughout the course of a day/week thus really not having a true sense of the hobby. Having an employee that works there part time isn't a help either, and then their is the money issue...
They are in business to make money and if selling you something due to misguided and false info, so be it is their motto! Now, don't think that this is the case with all pet shops, because I deal with a few that are fairly modest and informative. Fortunately I have been in this hobby long enough to know a snowjob when I hear it and can weed through the false accusations and information and make my own decisions without being persuaded one way or the other by local pet shops!
Their are many good books, and websites along with 3reef that can help you to be successful in the hobby and make it more enjoyable, rewarding and entertaining as well.