Live Rock Types

[BlkWolfe]

Courtesy of Darren Walker, aka Palmetto of Reef-Central

Beginner's guide to Live Rock

After handling (literally) tons of the stuff (and doing many things wrong along the way), I thought I might take a few moments to write a wordy post on the subject of Live Rock.

Live Rock is the foundation of our reefs, and is where the most significant biological filtration takes place in our tanks. Toxic nitrates and nitrites are processed deep within the rock by many forms of bacteria. Good quality Live Rock will come with more than just bacteria, however. Good rock will be populated with corals, worms, pods, foraminiferans, and many other interesting creatures. Various macroalgaes, snails, crabs, and other inverts often "hitchhike" their way in on the rock also. A few undesirable hitchhikers such as pest anemones, hairy rock crabs, mantis shrimp, and more may also come with the rock- although a 15- minute soaking in high-salinity water (1.030 SG) will run many of these out.

Here are some of the most common types of Live Rock with descriptions (IMO & IME!):

1) Fiji- This is the most commonly available live rock on the market. It is very porous, providing good biological filtration and a lot of rock for the money. (Because it is not very dense!) Fiji rock is also usually rather inexpensive, although the quality varies a LOT from one vendor to the next. (wholesalers included.) Premium Fiji is quite beautiful once cured and encrusted with the purple coralline algae this rock is known for- but if you order the cheapest online Fiji, don't expect much!

2) Tonga Branch- Extremely dense, branched coral skeletons that add a very nice look and natural appearance to a mixed reef structure. It can be very heavy and usually carries less "life" than most types of LR. I like small amount of Tonga Branch for a diverse appearance, but do not use it as the only rock in a tank.

3) Kaileni- WOW! Deep-water Tonga rock that has a wide range of shapes, sizes, and densities. Some Tonga branch-like rock is usually mixed in small amounts, but most pieces are the huge caves and arches that make aquascapers drool. Many foraminiferans, fire corals, and a wide range of wildlife is found throughout the rock. Some of it is porous like Fiji, other pieces are hard, flat shelves or branches. This is my personal favorite Live Rock. The rock was originally named after importer Walt Smith's daughter- pronounced in the tongue of the people who collected the rock. Just a tidbit of LR trivia for ya.....

4) Caribbean- Very cool shelves and big, flat branchy pieces. Has a lot of the characteristics of Tonga branch, but not as dense. The Caribbean rock I have handled has been Haitian(I think), and is absolutely FULL of worms. Spaghetti worms, bristle worms, featherdusters- I don't know why, but there are always dozens of worms in the bag the rock comes in- so I dump them in the Live Sand vats, hehe.

5) Aquacultured rock- There are also many types of "Aquacultured" rock out there that are either man-made or mined rocks that have been kept in the ocean until colonized by marine life. Most of the man-made rock is a mixture of concrete, shells, and aragonite. Mined rock is usually aragonite or Limestone base rock. The aquacultured rock varies greatly in quality and appearance, depending on who is doing the culturing! Depending on where it is cultured, some of this rock may also be more likely to carry unwanted rock crabs and mantis shrimp. Tampa Bay Saltwater and Gulf-View are two companies that have a reputation for providing very high quality aquacultured rock. I have also seen some really bad examples out there- so be sure you are dealing with a reputable company if you are purchasing "Aquacultured" rock!

6) Misc.- There are many other varieties out there that can be hard to pin down. Buna spiny branch is a very nice looking rock that looks to be some kind of ancient acropora skeleton. Marshall Islands rock is very high quality, but is imported in smaller quantities, and is more expensive. I have also seen other Deep-Water Tonga rock that appears to be very similar to the Kaileni- perhaps just coming in through different importer channels.

Personally, I like to mix types of rock. It is my opinion that the wide variety of shapes and sizes looks more natural, and also should provide greater biodiversity from a wider range of fauna from different locations. Several of the types I have listed have specific advantages, and I like to mix the flat shelves of the Caribbean with the Kaileni Caves and Fiji boulders, with a few branches thrown in for something different.

About "Curing"...

Fresh Live rock must be "cured" before adding it to an existing system, basically because there are many dead things in there that did not survive the journey. "Curing" simply means waiting for the dying stuff to die, rot, or be eaten- while in a separate system that will not be damaged by the ammonia spike created by the funky stuff.

I think the most common mistake is not having enough water volume to cure the rock properly. If you pack 150+ lbs. of rock in a 45-gallon rubbermaid (like I did!) you will create a noxious stew that will kill many of the small organisms off that may have survived. (And, your spouse will talk about that reek coming from the basement for YEARS afterwards!  ) Get the rock in as much volume as you can, such as a kiddie pool (perfect!) or large Rubbermaid trash can. You need as much circulation as you can get in there- drop a big pump in to churn the water if you can. Keeping the temperature high (80-82 degrees or so) will speed up the decay process and move things along. This is another common mistake: if the water is too cool, it sort of "preserves" the dead stuff, then it rots later- when you put it in your nice, warm tank! Hermits or snails can also help clean the rock up, but snails can only take so much of the ammonia. Frequent water changes are very helpful, especially during the first week- this is also when the smell reaches its peak. Sponges or other things that are rotting should be removed and the rock should be turned over/ blasted with a powerhead or lightly brushed with a soft-bristled brush to remove nasty stuff. I don't like scrubbing, because you remove a lot of worms and things that you might want to keep! I run actinic lighting over the rock as it is curing when possible, and reduce the photoperiod to a few hours a day. (Algae will descend on you if you give it too much light with all that goop in the water!)

After 3-4 weeks of this, the rock should be fully cured. I use my nose to tell me when it is ready, although I am told that test kits work also.

...If it smells like dead fish, put it back. If it smells like a jetty at low tide, it is ready. Be careful- sniffing LiveRock may kill brain cells-- or at least that would explain a lot after the tonnage I have sniffed! 

For those of you who enjoy your kits, we are looking for the time when ammonia, nitrate, and nitrate levels are zero (or close to zero).

I do not consider myself an expert (are there any?), but I do know a lot of things I have done wrong when handling Live Rock in the past. If there is anything I can help with concerning the curing or handling or Live Rock (or anything else), please email, post, or message me- I will be glad to share any of my mistakes and experiences.

Darren Walker