Well, Im not going to jump to conclusions, but I will assume you have had this tank up for at LEAST a month before you tried to introduce anything.
First of all. EXCELLENT choice on the soft coral route!
Thats awsome.
The tank may appear to have a LOT of room and most people when new to the hobby (reef keeping) jump the gun a bit and get as many little frags as possible to start "fillin' her up", However. Please refrain from doing this, as the temptation is strong, but rather add one at a time, maybe two. In the size aquarium you have, most soft corals in the wild, would outgrow that aquarium in no time. (and thats just ONE coral... not a group of them). Soft corals are great, they are easy to care for, but they do get big. Most soft corals are rather "tank friendly" to thier tank mates, however there are a few that will create a "chemical warfare" in your tank.
As far as chemicals go... Calcium is not entirely necessary, however it doesnt hurt. (im probably going to catch some flak for that but, I dont add any... EVER...) What is important to soft corals is Iodine, Strontium, and Magnesium. (Iron is at the bottom of the list)
Soft corals are pretty hardy, and a Protien skimmer is not necessary if you keep the fish to a bare minimum.. or none at all. The bioload caused from the fish, will require you to invest in one in no time. The bio load from just soft corals does not consititute the use of a skimmer. (There are many articles you can read through that discuss this thoroughly).
Water changes are important, so buy some salt and have salt on stand by at all times. God only knows what can happen when an Emergency batch of saltwater is necessary!!
(Been there.. done that).
Lighting is important, and I recommend that the lighting be at least 5 watts per gallon. (it sounds like that might be covered). Stony corals require more light and in there case.. more is better. 8-9 watt per gallon range.
Your water movement is covered. In that size tank you should be fine. (there are folks out there however, that will probably tell you to put a 900 gallon return pump on the thing on a closed loop... but thier NUTS
)
Temperature.... Make sure your tank temps dont reach 90 Farenheit! Try to keep it between 75-80!
I guess that about does it for the basics. Before adding a thing tho, make sure your Nitrates, Ntrite, Ammonia, and Phosphates level are all at ZERO and your salinity level between 1.023 - 1.025. If you can maintain these levels, your tank should do pretty good.
If you can keep those items in check, you'll be off to a better start than a lot of folks who take the plunge on thier first go.
***DISCLAIMER*** This is not ALL the information your going to need, and I suggest you read as much as you can, and be a sponge for the next..... however long your involved in this hobby. This site and others are full of great information that you will find beneficial, and at times... entertaining. Welcome to the hobby, and best of luck with your new tank!
Jaybo