There comes a time in this hobby when many aquarists grow bored of their beginner corals and they
become interested in small and large polyp stony corals (SPS and LPS, respectively). For those of you
who have been maintaining a “softie” reef (which includes coral such as zoanthids, mushrooms,
leathers, and star polyps), you may need to make adjustments to your aquarium or maintenance routine
in order to keep these beautiful stony corals thriving. This article will help guide you through how to
create a stable environment for SPS and LPS, and their required upkeep.
Since we are talking about a very broad range of corals, understand that each species has different
lighting requirements. LPS tends to do best in lower and moderate light, while SPS tends to prefer
moderate to higher lighting. There is much debate over what PAR rating is truly considered low,
medium, and high. Natural sunlight seems to keep natural reefs at a PAR of 1000-2000 based on some
studies I have read, greatly varying based on time of year and location. From my research, I would
consider anything under 100 low light, 101-300 moderate, and 301+ high light. Again, though, this is a
very rough estimate. Some corals like Acroporas like much stronger light (many report great success
with a PAR of 800 or more). The best way to know what coral you can support is to invest in a PAR meter
or rent/borrow one from a local reefer or fish store. I highly recommend doing this before venturing into
more expensive, less hardy corals. Metal Halides, T5 high output bulbs, or quality LEDs (there are many
low quality, cheaper LEDs marketed for reefs these days that will not support coral) are the best option
for these corals.
This is where many people fail in keeping SPS and LPS. Many people will add a new coral to their tank
and not realize LPS and SPS use up calcium, alkalinity, and magnesium much faster than soft corals. And,
many people will not test their parameters and will not know when one of these experiences a swing or
sudden drop, which is the biggest cause of the corals demise from what I have seen. When adding new
coral, it is important to test your water daily for the week after introduction and learn how much
alkalinity, calcium, and magnesium your new coral(s) use so you can adjust your dosing. Aim for a
calcium level of 380-440, magnesium of 1300-1400, and alkalinity of 9-10. These numbers are all
interconnected, a higher calcium reading will require you to keep a higher magnesium and alkalinity.
Nitrates and phosphates should be low, but not zero (2-5 and 0.01-0.06, respectively). Too high or too
low of these parameter can be detrimental to these coral as well. LPS is typically more forgiving than
SPS, and can tolerate nitrates and phosphates being a tad higher. A constant temperature of 76-80
degrees Fahrenheit is ideal.
As with everything, this varies depending on species. But, generally, giving SPS moderate to high flow is
ideal. They have small polyps that easily build up detritus, and don’t have long feeding tentacles. More
flow keeps your sticks clean and well fed!
LPS is a bit different. They vary much more between species on what type of flow they prefer. Generally,
Acans, Blastos, Cynarina, Donut Corals, Duncans, Elegance, Fungia, and Bubble Corals prefer low to
moderate flow. Scoly, Chalice, Favia, Favite, Caulastrea, Euphyllia, Brain, Goniopora, and Cup Corals
prefer moderate to high flow.
These corals generally appreciate feeding more than the typical mushroom and xenia colony. SPS and
smaller polyp LPS (like Chalices) prefer a mix of prepared powdered coral foods, liquid coral foods, and
phytoplankton. While other large mouthed LPS will happily accept these, they also benefit from larger
meaty foods like pellets, mysis, brine, or even krill. When feeding, you will see feeding tentacles appear
on your corals. This is normal, and they may show these tentacles if they are hungry and need a feeding!
This can be tricky. Since most SPS prefers high light and higher flow, most SPS reefers would recommend
placing in them within the top third of your aquascape. Some LPS prefers being on the sand, such as
Scoly, Elegance, and some Brain Corals. Others need to be kept on your rocks, and can be placed
anywhere that your PAR matches their needs. However, keep in mind that as coral grow, they will
inevitably run into each other. Some corals, like Chalice and Euphyllia, are notoriously aggressive and
will sting neighbors. For this reason, it is best to keep about six inches of space between these and other
corals. SPS is generally less aggressive and can be placed within a much closer proximity of each other.
Because these corals are known to give beginners trouble, it is safe to assume that there is a list of
problems that may arise for first time SPS or LPS keepers. Here is a list of common ailments these corals
If your coral is bleaching, it is likely due to too much light. This is common in new additions as many
wholesalers and local fish stores keep corals under low light and hobbyists often forget to acclimate
them to their brighter lights. Try moving your coral down and in a more shaded are.
Turning tan or brown
Another common issue with new SPS and LPS keepers, “browning out” implies too little light. Many soft
corals can survive in very low light conditions. If you are using a weaker light, it may be time to upgrade
if you wish to keep these corals. Try moving the coral upwards on your rocks or turn up the intensity of
your light fixture.
If your new coral isn’t bleaching or browning out, but just seems pale, check your nitrates and
phosphate levels. Many times this is caused my too low of nutrients in a tank that causes the
Zooxanthellae to starve or lose color. If your levels are too low or at zero, raise your nutrients.
This is typically caused my too little, or too high flow. If your new coral seems closed up in an area of
high flow, try moving it to a calmer area (or vice versa). Euphyllia can be quite particular about what
flow it likes, so it is important to watch new additions for signs of distress!
Tissue Loss or Damage
Tissue or flesh issues are caused by a number of things. First, check your parameters. A sudden swing
can induce tissue necrosis. If everything checks out here, make sure the coral is in a proper flow and
lighting area for the species. If those both check out as well, pull the coral out and dip it in a coral dip. I
prefer to use iodine. This will show you if there are pests (like flatworms) in your tank that could be
potentially eating or irritating your corals. If you dip and there are no pests that fall off, it can be safe to
assume that a fish in the tank is taking little bites out of the coral when you aren’t looking. Angels, Toby
puffers, wrasses, and crabs are the usual suspects. Sit further away from your tank than usual and
observe for an hour or so to see if you can identify the culprit! If the tissue appears to be falling off
extremely quickly, frag off healthy areas and dispose of the dying parts as there are some diseases that
will kill an entire colony within a few days, and fragging is the only method of saving the coral.
A tank full of SPS and LPS can mimic a natural reef more than a soft coral tank usually does. They are
beautiful corals that can easily bring life to an aquarium. For many of us, the joy of keeping these more
difficult corals comes from the feeling of pride and accomplishment at being able to care for corals that
not every reefer is able to. It sets us apart from beginner tanks, and shows that we are in tune with our
systems and understand all of the mechanics that take place within it to provide a stable home where
these corals can flourish. If you are ready for a challenge with great reward, LPS and SPS keeping may be
right up your alley!