The SPS coral genera generally include Acropora, Pocillopora, Montipora (Fire corals), Stylophora, Hydnophora (Horn Corals) and others. SPS stands for Small Polyped Stony corals because these corals all have small polyps on a hard calcium-based skeleton. Many varieties branch out.
Bright lighting and very strong currents are the two most determining factors for success with these corals. VHO (very high output), HO / PC (Power Compact) or, preferably, MH (Metal Halide) lighting must be utilized. The 6500K MH bulbs are the best for these corals, even though others, like the 5500K, will also do fine. The 10000K tends to have a very short bulb-life and a much worse spectrum in comparison. These corals will not live under regular coralife fluorescent bulbs and will slowly starve to death. Place all SPS corals up high in the tank so they get max light.
Strong currents can be accomplished through trial and error. The idea is to have the current go around the coral, not directly at it. Experimenting with this is essential. If a coral is not opening, it may be getting to much direct current for example. A wavemaker is not necessary, but could prove a valuable tool. More than likely, two or three well-placed powerheads will suffice.
If one includes the unnamed discovered Acroporids, then more than half of all corals described are Acroporids. 368 have been described, with 150 being named.
Even thought these corals are easy to break, they have a very strong skelton, comprised of the typical Calcium Carbonate, arranged in honeycomb shapes, lending to a light weight and incredibly strong structure.
Acropora have evolved specialized polyps for breeding and other things. This is very unique.
In the wild, some Acropora are able to grow 10 inches in a year. In some reefs, they cover more than 80% of the reef. They come from the reef flats in water than is very turbulent, which is one reason why they need such strong light and currents. They overtake many reef sections where other corals can not grow, due to the high currents, etc. Their main "defense / offense" seems to be that they overgrow and overshadow other corals, cutting out the light they get causing many to starve.
These corals can be propagated by breaking off pieces in a specific manner, but that will not be covered here now. The important thing to remember is that they can be easily broken in shipping and through bad handling.
Calcium levels have to be very high, 420-450 is best, and under 400 you will have trouble with them growing as quick, etc. Strontium and Iodide should be dosed as well, and nitrates have to be kept under 7ppm, preferably under 5, at all times. This should be standard for most reef tanks though. A Kalkwasser drip-system is hands-down the best way to introduce calcium into your tank. The water temperature must also remain pretty consistent.
As far as feeding goes, they do not need to be directly fed, but we may find in the future that this is a good idea. The Acropora and the Fire Corals are the hardiest of the bunch, relatively speaking, if their conditions are given.
The Fire corals are rather hardy, very aggressive, and grow faster than many other corals. There’s an encrusting form as well, and a Red Fire Coral (which, under speculation, may not take in light).
The Pocillopora need more light than any other SPS coral. Very good Metal Haloides must be used. Some of the hardy species may live under Power Compact lighting, but they will turn brown and lose their color. The coral of choice for Flame Hawkfish to call home P. elegans and P. dioux
The Horn Coral, Hydnophora rigida, can be very hard to keep and is extremely aggressive. The same goes for H. pilosa.
Seriatopora hystrix can also be iffy sometimes. It may do great, or it may die very shortly. Alot of room to grow, bright light, strong current, and other parameters mentioned above will greatly increase success, and it can be hardy under certain conditions. They grow near the surface in nature. It’s also called by the common name of Bird’s Nest Coral.
The Green Staghorn and the Pink Staghorn (Acropora cervicornis and A. nobilis) are great species that are moderately hardy if their conditions are met. They’re very pretty, and the green one supplies fish with great refuges, such as Green Chromis, who base their schools around such colonies. Other interesting Acropora are the Green Fiji (A.bushyensis) (The green one pictured above), the Blue Acropora (A. loripes) (pictured to the side), and A. nana or samoensis or divartica.
The SPS reef tank requires more money and more experience to setup, but has a unique look to it’s own. Some prefer the gracefulness of soft corals, however these offer something totally challenging and unique that can be a great centerpiece to many reef tanks. More on SPS in the future!