Kirk,
As bad as it sounds, you really need to take back anything live and get store credit for later, and start over. You mentioned it was ***** where you bought your stock from. If they wont give you credit, find a place near you that will and convert your business to them for all future purchases.
For your 55 gal you need around 50-60 lbs of live rock to get started. I would buy from an online vendor, such as this site, or any other, uncured liverock so that you may cycle without harming any storebought livestock.
You also need to decide if you want to maintain a sandbed for additional filtration. If you do, use the calculator on the left of this page to see how much sand you need to get started. I started with live sand at first and 6 mo ago switched to bare bottom and couldnt be happier. If you buy livesand, buy legit livesand not home depot sand which will release silicates and cause algae blooms.
Once you decide on substrate, mix up salt mix with reverse osmosis de-ionized water. If you use tap water you will have horrible problems with loss of life and algae. You can get RODI water at walmart or any quality fish store(LFS). You can also but your own RODI unit from an online vendore and set it up yourself.
Let the rock and sand sit for a month (more or less depending on test outcomes) with lots of flow. For flow you need powerheads that will move large amounts of gallons per hour. On my 58 gal I have 2 maxi jet 1200s, 1 MJ 400, and another MJ900 for my skimmer. I use an aqua c remora hang on skimmer which you can also find online for fialry cheap. The skimmer will vastly improve water quality as compared to a reg filter. Once your tank is stable with tests running-ammonia 0, nitrite 0, and nitrate +/-20ppm you can now add some snails and hermits to clean up any algae.
I replace any evaporation with RODI water and do I 5 gallon water change with 24hr old mixed salt and RODI water once a week. This will help keep your levels(nitrite, nitrate, ammonia) in check. You should also shoot to maintain a specific gravity of 1.025 at all times. Specific gravity is the amount of salt in the water. The best way to test for this is with a device called a refractometer witch is also avail online at many vendors.
Once everything is testing 0 (or for nitrates less than 20) you may add 1 small fish and wait at least 2 weeks to be sure your tank is ready to sustain new livestock. After 2 weeks perhaps add 1 more fish and replenish some of your cleaning crew but not many new creatures at once.
If you can successfully do this then you are ready to maintai n you own personal world of life. If this seems like too much for a simple fish, then perhaps it is the wrong hobby for you. Remember, anything you put in your tank is that animal's one chance at life so it is you responsibility to maintain it.
After having extreme patience in the beginning, this has been one of the most rewarding experiences in my life. Please respect the task you are undertaking. Good Luck! PM me if any questions, I check this site daily.
