thinking of staring a salwater tank

Oh boy, there is honestly too much to get into in one answer. However, this question has been asked many times before on this forum. Do a thread search looking for titles just like yours during the last three or four months. The short answer to your question of "what will I need" is:

-Instant Ocean salt mix
-a hydrometer or refractometer
-a reliable heater
-a good powerhead
-sand or crushed coral for your substrate
-live rock (recommend 1.5-2 lbs per gallon)
-lighting (3-5 watts per gallon for corals)
-a test kit for ammonia, nitrite, nitrate, PH, and alkalinity
-a LOT of patience

Read Fenner's "The Conscientious Marine Aquarist" for details and knowlegde from a master. Anything published by Tullock or Shimek is good reading as well. Oh, and LFS stands for local fish store.

Check out the archives, and feel free to ask any questions you might have. It sounds corny, but the only bad questions are questions not asked. Welcome to AC!

Well, let's say you want to have Xenia, and other soft corals.

The very first thing is to get the Fenner book, Eric Borneman's "Aquarium Corals," and probably John Tullock's "Natural Reef Aquariums," and read them cover to cover. In some ways, reefkeeping is easy, but it depends on knowing what's happening in your tank.

Everything on Kreblak's list is good, but add more patience. For a reef, I'd say the canister is not of much use. I would recommend a good skimmer, like a CPR BakPak (maybe too small), or better a AquaC Remora plus. SOme will say a skimmer is not necessary, and they may be right, but I think it's especially useful when the tank is young. Also, circulation is critical. I turn my tank over about 15-20 times/hour, in addition to the skimmer. Powerheads or a closed loop are the way to go, IMO.

In some ways, Xenia is relatively hardy, and some even find it to be a weed. It does require strong lighting (~200 watts for your tank, IMO), and a steady pH above 8.1. The approach I'd suggest is to upgrade your lighting, get your live rock and sand, cycle your tank, and then get a few easier softies like green star polyps to start off. Once everything is stable, go for the Xenia. Expect the process to take months.

Once you start to get down to details, ask a lot more questions. There's never a shortage of opinions here.

A sump is basicly an extra water vessel(usually in your stand below the tank) which gives you the following benefits: Larger water volume, place to hide equipment(skimmer, heater), and it can make water changes easier. You can also incorporate a refugium (usually a tank/space with a DSB and macro algae) which will aid in nutrient export and pH stability.

That being said, while a sump is beneficial it is not a necessity. Many people(including myself) run successful reef tanks with out a sump.

Brian

What Brian said. I am also sumpless. It would be a bonus if I ever wanted to run a Ca reactor, and would make setting up the auto-topoff system easier.

Now is a good time to decide whether you want one. You will need a way for the water to get from the tank to the sump. From what I have seen and read, life is much better if the tank has drilled overflows going to the sump, rather than being dependent on siphons.

Softies are soft corals that do not form hard skeletons like hard corals do. All corals need a lot of light, but softies need less calcium and various other minerals.

To elaborate a little, "softies" are octocorals. They actually in a separate class (alcyonaria) from sony corals, anemones, zoanthids, and "mushroom anemones" (which are all in zoantharia). There are many differences, from stony corals, the most noticable being that they are supported by sclerites embedded in their bodies, rather than having a solid skeleton. There are exceptions, like Tubipora (pipe organ coral), which has something like a skeleton, although it is constructed of fused sclerites. Another obvious external difference is that soft corals' polyps have tentacles in multiples of 8, rather than the multiples of 6 found on stony corals and anemones. These tentacles have little side branches, making some of them look feathery, while those of stonies and anemones are unadorned.

Commonly seen genera include Sarcophyton (toadstool leather), Sinularia (finger leather), Pachyclavularia (some say Briareum, green star polyp), Clavularia (clove polyp), Capnella (Kenya tree coral), Tubipora, Xenia, and a bunch of others.

One other issue about soft corals, which seems to be dramatically different from stony corals is the production of toxins. Some species, like most Sarcophyton, produce toxins that can affect other corals in the tank. This is one reason that it is often recommended that soft and stony corals be housed separately. I keep both, and (knock on wood) activated carbon seems to do the job pretty well.

Like hard corals, octocorals are extremely diverse. Both groups have many species that are photosynthetic, and there are differences among them regarding how much light they require. Both groups also include many non-photosynthetic species, which must be fed.

There are some soft coral species, like green star polyps, that will grow very nicely at 3 watts/gallon, while others, like Xenia, require more intense light to thrive. With few exceptions, all tend to grow better with more light.

That's a few paragraphs. If you want to get a more thorough, and probably more accurate, view, check out Borneman's book.

If you want to start with less light, maybe mushroom corals (corallimorpharians) would work. I've never tried them, but they are supposed to be less light-dependent, and some species even fare poorly under intense light. They are also supposed to be more forgiving of tank conditions.