I had two salt water tanks. My advice is this...

#1 Do some serious research before you do anything. Do some reading on salt water fish, go to fish store and talk to some of the "experts" in the salt water section. (stay away from the name brand pet stores like PetCo and those others that just happen to sell salt water fish)

#2 Don't get anything smaller than a 50 gallon tank. Why? The larger the easier to keep the ph balanced. I recommend getting a 100 gallon tank to start off.

#3 Expect on a 50 gallon tank to spend at least $1k to do it right. Why? That will include the tank, nice stand to hide all the stuff you need under it, a nice amount of live rock (the more the better....will explain), and proper filtration.

#4 Don't be cheap on your protein filters and other filter systems.

#5 Don't get plain sand when you start tank, get several bags of live sand for tank. Why? Live sand contains bacteria needed to help get your tank set for your 1st fish.

#6 Dont expect to have a bunch of fish. I would say about 3 fish for a 50gallon tank.

#7 Dont expect to put any fish in your tank for at least a month. Sounds strange, but it is better that way. Spend first month getting pH levels set and get good bacteria growing. Feed the tank as if you did have fish in the tank. Sounds strange but it helps.

#8 When ready to add a fish, get maybe (2) of the cheap fish that cost maybe $1 - $5 bucks ea.

#9 Expect those first two fish to die Sucks but thats why you get the cheap ones.

#10 After about a month of keeping 2 - 3 cheap fish alive and having everything set, and having that water looking crystal clear all the time. Then after about 2 - 3 months total you can add the real nice fish.

#11 Expect to spend some serious cash on your nice fish. Thats why you want to have your tank ready when this time comes.

#12 Make sure you dont get too many agresive fish.

#13 Be carefull putting your hands inside of tank, some of those salt water fish can kill ya

#14 If all goes well this will probably be the beginning of a serious habbit that is hard to break. You will start off with one tank and if it works out well you will end up with several.

Enjoy, I hope this helps. If you would like me to recommend some of my books I have just say so and I will post them.

Also remember that most salt water fish are right out of the wild, most are not farmed in the US. So please if you are going to embark on this, take your time. There is no rush. Remember the ocean has been around for ever. You are trying to recreate it in your home. So as in real life, the longer the better.

Also you may want to try brackish tank first. That will get you into checking pH levels and working with salt. But it is much cheaper. If you can master that, and if you like it then get your full scale salt tank.