Stony trouble

Question
I have consistently bad luck maintain stony corals.  The newest victim is an
Elegance Coral that started dying off after a few days from the store.  The
water chemistry testify perfect at the store.  They couldn't check the salinity.  
My last water change was 90 days ago.  I've always done fine with soft corals
and fish.  Stonys including torch and hammer have always been hard from me
to keep alive.  The tank is 85 gallons.  I run a chiller at 79 degrees, protein
skimmer,  PhosBan, algae filter (with a chamber of bio balls) and slow drip RO
with Kent liquid calcium.  I dose Iodide and Strontium weekly on separate
days.  My lights run 10 hours and consist of a pendant single bulb compact
metal halide (Aquaspacelight) supplemented by a pair of the new T5's.   My
metal halide bulb is about 2 year old so I will replace it.  An thoughts on my
stony troubles?  

Answer
Hi Eli. Usually when stony corals fail to thrive in a tank it is because of two possibilities. Water quality being number one and lighting being the second. Most stony corals do not acclimate well to a new environment and sometimes even the simple change in lighting or water quality can do them in. Stony corals do not tolerate nitrates and if you have any at all this could be the problem. You said that your water tested perfect so I am guessing you are at zero ammonia, zero nitrites and zero nitrates. Your temperature should be somewhere between 80-84 degrees F. and salinity kept at about 35 ppt(1.027). PH should be maintained between 8.2-8.4 and calcium around 450ppm. That is the ideal environment for stony corals. As for lighting you should have about five watts per gallon of whatever type bulbs you use. Your metal halide is a little old and should be replaced every 6 months to 1 year for maximum performance and light output. You told me the kind of bulbs you have but you did not tell me the wattage so I really can not comment on that further. As for the elegance coral, these are an extremely difficult coral to keep and if you are having trouble with some of the easier hard corals like the torch and hammer corals then keeping one of these will prove to be very challenging. They are sensitive to the presence of soft corals and may be adversely effected by caulerpa algae. They succumb to infection easily, are prone to bristleworm irritation and can be easily punctured when handled leaving them susceptible to brown jelly infection. In short they are quite frequently problematic. The majority of elegance corals do not survive in a tank environment. As an added note I have read many studies about the addition of iodine to a reef tank and they have all come to the same conclusion. It is not necessary and can if even slightly overdosed be more detrimental to corals then a help. Seasalt mixes contain this trace element in the right proportion and the addition of iodine should only be done if partial water changes are not being done as often as they should. I hope you are using an iodine test kit to ensure you are not overdosing your tank. This would be a very fast killer of most stony corals added to your tank, as well as some soft corals(some xenia will die instantly with the addition of iodine to the tank). In short there are some corals that should just not be collected and sold in the pet industry. Elegance corals are one of them. There has been a great impact to these corals due to the over harvesting of them to keep in tanks where the majority of them fail to thrive. It is up to the retailers to practice responsible husbandry by not keeping delicate species like this for sale. They are beautiful and hard to resist but even more beautiful in their natural environment.