im kinda stuck as to how to choose what type of tank to go with whats the diff between saltwater & reef and saltwater & nano reef
Saltwater is the generic term for all different types of tanks. Typically they all run a salinity around 1.025 SG. Then you break them down into groups;
Reef-These tanks have corals. Lighting requirements are specific and can be the most costly part of these tanks, apart from the livestock. Certain fish cannot be housed in Reef tanks as they eat corals. Water maintenance is more critical in these tanks as most corals need better water quality.
FOWLR (Fish Only With Live Rock)-As stated, these tanks only have fish and a rockscape. Lighting is not important and almost any lighting system can be used, even the T8 lights from your old Freshwater system. Any type of fish should be suitable for these tanks. Most predator fish seem to be housed in FOWLR tanks. Good starter point for new hobbiests as these tanks can normally be upgraded into Reef tanks later once you get more experience. Water quality is not as important here, and again that makes it a good starter tank to learn how to control excess nutrients.
Nano tank-A generic term for a smaller tank. In the saltwater world, smaller typically means anything less than about 30 gals. Maintaining stable salinity can be an issue (due to evap) as well as water quality due to a lack of "inertia" in the water mass.
Pico Tank- really small tanks, about 10 gals or less. Not really suitable for any fish, but can make nice office reef tanks with corals and invertibrates only. Imagine a small 4-5 gal desk tank with just some pulsing xenia and maybe a zoa colony, along with a hermit or 2 and a shrimp. Unfortunately, when things go wrong in a small tank like that, they go wrong fast.
I think a nice starter (and where I started) is a larger nano FOWLR tank. I learned about nitrate management and continued my research before my big upgrade.
Good luck