In the previous article we covered the basics of live rock now we will get into some more details concerning live rock.

What is Coralline Algae?

Coralline Algae is a hard calcerous algae that often grows on live rock after its been in the tank under suitable condition for an extended period of time. This forms on the rock from spores that survived the shipping and curing process. It will initially show as a hard white spots on the rock and as it gets larger becomes colored. Healthy Coralline Algae that is growing will have white edges and the rest of the growth will be colored. Coralline algae comes in a wealth of colors with some of the more common types being Purple, Red, Pink, Orange and Green. . It can take on a couple of different growth forms such as plating giving the rock work a rough and crusty look to it, but it most commonly grows in an encrusting form which makes the rock resemble an M&M Candy that’s been dipped in a candy coating or gives it a painted on look.

Why is coralline Algae so desirable?

Its desirable because of the algae’s striking colors that it comes in. But more important than aesthetic appeal is the functions it performs for the reefer when present on the rock. Some things that coralline Algae does for the Reefer other than look pretty is that it being a plant requires nutrients to grow. As Coralline Algae grows it will up take nutrients from the water and help keep the water pristine and clean. The other added benefit to Coralline Algae growth is that where it grows… nuisance algae can no longer grow in that spot as long as the Coralline Algae is alive. So it looks cool, cleans the water and prevents unwanted algae growth in the reef tank.

How long will it take for my rock to get covered in Coralline Algae under normal conditions?

This is akin to asking, “How long is a piece of string”? Generally speaking it will take at least 6 months to a year and a half to get good heavy growth and coverage of Coralline Algae on the rock work. This will be depended of course on many factors such as water flow, Lighting and its intensity, water quality in respect to being clean and having the right minerals available in the water not to mention how much Coralline algae was present on the rock that survived the curing process.

What kind of water flow is best?

Generally speaking Coralline algae will grow in just about any type of water flow conditions. However it does best and spreads fastest in fairly brisk water flow. This occurs for several reasons. First the water flow will spread the Coralline Algae spores around the tank better effectively “contaminating” the rest of the rock surfaces in the tank so to speak. Higher water flow will of course ensure there are plenty of nutrients around for it to feed off of as well, but it will also keep detritus from building up on the rock surfaces thereby inhibiting the spread of Coralline Algae. Most reefers with Hard corals strive for water flow that is 10 times the tanks water volume. For example a 100 gallon tank should have a flow of 1000 gallons per an hour or more! Reefers with Soft corals will normally shoot for somewhat less than this depending on the corals kept. Another aspect of brisk water flow is that it will keep detritus from building up in the nooks and crannies of the live rock and creating excellent conditions for the growth of nuisance Algae. This is often a common problem for Reefers, especially those new to the hobby and can quickly reach plague proportions in intensely lit Reef tanks.

To further prevent this, your rock work should be blown down weekly with a Powerhead or baster (used in cooking). This will remove the gunk that will eventually build up as the rock performs its biological function of cleansing the water. With brisk water circulation this “Gunk” should stay in suspension long enough to be removed from the water buy the filtration system.

What kind of lighting is required?

Coralline Algae will grow well under a variety of lighting types and intensities such as NO (Normal Out-Put), HO(T-5 High Out-Put) VHO(T-12 Very High Out-Put) PC(Power Compacts) or Halides. As such it hard to go too far wrong when it comes to lighting to grow Coralline Algae as just about any light will do. One key thing to keep in mind is the light spectrum of the light. Generally speaking, you will want to use lights that have a Kelvin rating of at least 6500K. Most Reefers use 10,000K to 20,000K lights. This temperature of lighting contains more light rays in the blue spectrum of light and less red and yellow light waves.

What level of water quality is needed?

Coralline algae will grow nicely in your average Reef Tank as water is typically clean and has a low bio-load in it compared to most Freshwater Tanks. When you follow the typical 10% monthly water changes you will replenish any needed trace elements and the waters quality will not deteriorate too much. Fresh mixed saltwater typically contains all of the needed nutrients, buffering agents, proper PH etc…need for Coralline algae to flourish.

Some personal observations;

To speed up Coralline algae growth I have found that there are many things one can do to obtain quicker than normal results.

Seed the tank! Seeding the tank is an expression used when one would add more Coralline Algae spores to the system. Coralline Algae Spores can be bought from some on line vendors. Another technique is to add GARF Grunge. This can be obtained from www.garf.org and although a bit pricey can do wonders for a tank. It’s extremely rare that I do not start a Saltwater Tank with out a few pounds of this being added. www.premiumaquatics.com also sells a similar product called “Crude”. This is essentially the “crumbs”, “rock chips” and small rubble found at the bottom of Live Rock curing vats used by commercial dealers. This stuff is often loaded with a variety of bacteria, beneficial to the tank and coralline algae spores of almost every imaginable strain. Another way to obtain spores would be to get the scrapings of Coralline Algae from a fellow Reefers tank after they have cleaned their glass or tanks equipment. When these “scrapings” are added to a tank the current will carry them around far and wide. As it settles onto the rock work it will eventually grow. If you’re running a skimmer turn it off for a few hours when doing this.

Proper water conditions; the water should be from 78-80 degrees, Ph should be 8.3-8.4, Ammonia, Nitrites and Phosphates should be near undetectable. Nitrates should be 5 ppm or less. Calcium should be at least 430-450 ppm, and KH/GH should be between 110-125 mg/L. I will normally slightly elevate the Magnesium, and Strontium levels in the tank.

Lighting

I have also found through experimentation that Coralline Algae grows much faster and I can maintain more varieties of colors when the light is not overly intense. When I start a new tank and want to accelerate the Coralline Algae growth I will use lots of NO & VHO lighting and favor lots of actinic light. These are bulbs that are “blue “ in color and produce light waves primarily in the 420 nm range. PC bulbs are not favored for this as their light waves typically peak at 450 nm and as such leave a bit to be desired. Typically I will run two 36 watt Blue Moon Actinic T-8 bulbs 24/7 in conjunction with 2 x 110 watt VHO bulbs ran 12 on 12 off, one Actinic and one “Day Light” bulb. This I have found to be optimal. As light intensity increases there is less variety in colors and shades of Purple begin to dominate.

***These are purely personal observations and as such I have no “Scientific” facts to base this off of, so your mileage may vary…