To set up a fresh water aquarium, you're going to need your tank, your strong stand. Remember water is very heavy, so you want to go with a designated aquarium stand. You don't want to just put a fish tank on a piece of furniture. I've heard nightmare stories, where the stand just collapses three months down the road, so you want to make sure the stand is very, very strong. For the filtration system, there are a lot of options. You can have a canister filter which goes in the cabinet, I prefer a canister filter for a freshwater aquarium because it is silent, the hoses run off the back of the aquarium, you can pack whatever you want inside the canister filter.
Aquarium Set-up - Doctors Foster and Smith
Monitor your water parameters closely during this time. Check the salinity or specific gravity, pH, ammonia, nitrite, nitrate and carbonate hardness levels and correct as necessary. Ideally, you want the following readings for your saltwater tests before you start adding fish to your saltwater aquarium setup:
Setting Up An Aquarium - PetSmart
The next problem that will occur is one that I believe gets little attention in the hobby but is probably responsible for more fish deaths than ammonia toxicity. This problem is high nitrite concentrations. Once the bacteria that convert ammonia to nitrite (called ammonia-oxidizers) start working, the nitrite concentration in the water will start to increase rapidly. Unfortunately, the bacteria that convert nitrite to nitrate (the nitrite-oxidizers) are even slower growing than the ammonia-oxidizers. In our research, we saw that the nitrite concentration in the same newly set-up aquaria, as described above, reach concentrations of nearly 10 mg/L. Furthermore, the nitrite levels stayed high for several weeks. Usually the nitrite concentration does not drop before 0.1 mg/L until 25 to 30 days after the aquarium is first set up.
Beginner's guide to setting up your first aquarium - Aquarium Info