The encrusting Red Algae of marine aquariums are mainly of the non-jointed calcareous Subfamily Melobesioideae ("Mellow-beas-ee-dfpoy-day-ee"), in the Family Corallinacae (Order Cryptonemiales); they appear as thin crusts or nodular ridges. On close observation these films of cells are composed of calcite shells. Commonly seen are Lithophyllum, Porolithon (a major component of many algal reefs), Melobesia and Lithothamnion.

The branched forms of calcareous red algae are mainly members of the Corallinaceae as well; but in a different Subfamily, the Corallinoideae, comprising the jointed (or articulated) corallines. Both groups are worldwide and common in tropical to sub-tropical seas. Most often seen are the genera Corallina & Bossiella.

Other forms of red algae are more typically soft and string-like or flat sheets in body (thallus) shape and flexible in texture.

More coralline growth please. I need it now and I need it fast! - 3/31/04 
I ordered life rock from live aquaria and it seems like it's really taking a long time to grow coralline algae or really anything at all. <Is the tank fairly new??> it is still brown, green, and white. I had the live rock for six weeks. <Hardly enough time for coralline growth, my friend. One thing that I can tell you from my experience is that it usually takes a well established tank (aged) before rapid growth occurs. Also, lots and lots of patience. Nothing happens in fast forward in reef aquaria except deterioration and destruction. Please look at our FAQs on coralline algae for more information. Also there are some things you can do to speed up the process slightly. Here is some info I have gleaned from GARF and other sources: The answer comes in four stages, lighting, supplementation, GARF'S grunge product (lots of coralline diversity) and the most important ingredient..........PATIENCE. 
COOK BOOK METHOD FOR GROWING CORALLINE FASTER 
Use Instant Ocean TM (most any salt mix will work but this is the one I use) 
Use 2 - Triton And 1 - Blue Moon 40 watt bulb per 55 gallons (Or basically more actinic lighting) 
Use a phosphate removing filter 
Use carbon 
Treat tank with Sea Chem - Reef Plus TM. Reef Complete TM, and Reef Calcium TM 
- 2 times usual dose three times a week - These are liquids are added to the reef water. 
Use Sea Chem Reef Builder in make up water every other time you add make up water. We use two teaspoons per gallon. 
Use Sea Chem Reef Advantage in make up water every other time you add make up water. We use two teaspoons per gallon. 
Add lots of types of coralline to start - Just like putting seeds in the garden 
Calcium is one of the most important things to add to your live rock growing tanks. Calcium levels in your live rock grow out tanks should be kept above 400 mg/L at a specific gravity of 1.024. We have found that by using Seachem's products we have no trouble keeping both the calcium and alkalinity at the proper levels for rapid coralline growth. This simple method of treating our make-up water also keeps the Strontium and Magnesium level in our grow out tanks high enough for the coralline algae to thrive. We are certain other products will work fine, but these products are inexpensive and are proven to work. You must keep the Phosphate level in the live rock grow out tank very low. Protein skimming is important in the grow out tanks because it controls phosphate. Make-up water can be a source of phosphate. You may need a reverse osmosis or deionization system if your water source is high in Phosphates. Feeding is the most common source of high phosphate levels. We use a phosphate removing filter in tanks that are not producing coralline algae fast enough.> 
I followed there directions that was sent with the rock. 
<Instructions for what? Acclimation?>
I was wondering if it's going to change and if yes how long will it take or does it sound like it's dead 
My tank conditions are 
1.a Coralife 96 watt light 
2.my calcium is at 450ppm 
4.my ph is 8.4 
5.my nitrate is at .25meg 
6.I have a wavemaker 
7.two whisper filters 
<Sounds fine. You are well on your way. Now a little patience, maybe some of the above will help. Be sure to test often and watch just in case the system becomes unstable as you will be pushing the limits of reef water chemistry. Hope this helps. ~Paul>