Let's also factor in the live rock (or lack thereof). Cured live rock acts as your filtraton system removing ammonia and nitrites from your system. If the tank came with live rock it must be kept wet or the animals living in the rock will 'die off'. If the die off is high then once you add the rock to the tank your ammonia level will skyrocket and you will have to cycle the tank from scratch. That could take a while. I would also add a bag of live sand to the system.
Marine tanks are completely different from freshwater tanks. Read, read, and read some more. I would take Frank's advice and ask the store to 'babysit' your fish until the tank is ready. You may have to pay rent during this transition but it's well worth it. Take your time and get it right, you'll not regret it. Also heed Frank's advice and DO NOT use tap water. RO or RO/DI water is the way. Most LFS sell RO/DI water really cheap. It's $1 for 5 gallons at our local saltwater store here.
Check out
http://www.wetwebmedia.com , great reading there.
jake wrote;
You don't want to use tap water - use RO (reverse osmosis) or distillied found in most of the larger supermarkets.
You need a marine salt such as Instant Ocean. Do you have a hydrometer (?), the specific gravity of salt water is 1.026sg - about 1/2 cup of salt per gal. - Temperature, 78º - pH between 8.0 & 8.3 , ammonia/nitrite = 0, nitrAte - 20ppm or less, alkalinity (hardness) between 8 and 11dKH. Have a protein skimmer (?) - Aqua 'C' Remora is a good one for the smaller tanks, 55 gal. and up, I would get the pro ($200.00 or less).
CO2 accumulates while oxygen levels drop if the bags are closed. pH drops, ammonia levels rise, temp. changes, bacteria increase, etc. - a few hours, tops! A drop or two of AmQuel and NovAqua per bag would sure help if you have them. AmQuel will neutralize ammonia, NovAqua willprovide slim coat protection and stabilize pH.
This is mainly a freshwater news group, but there are a few marine tank keepers here.
Hope you know about the 'nitrogen cycle' (?). Well, with the fish in the bags, you don't have time for it! As soon as you can, go to a pet store that has saltwater fish. You need to get some of their established filter media and *fill* your filter with it. Better yet, ask the store owner if they would house your fish untill you can do a fishless cycle (anout 10 days to a couple of weeks.) ......................... Frank