The articles are the same for saltwater as with freshwater in regards to cycling It is the same process. I am with Rich, the pure ammonia is cleaner and won't stink up your house.
The 48" glass hood set is comprised of 2 24" hoods. They are not exactly 24". They are made to fit 55 gal
tanks. But you need to know if you have Perfecto, All-Glass, or Oceanic tank. The different brands have different sizes. I made the mistake of ordering 2 24" hoods and am now stuck with 4 24" hoods (2 All-Glass and 2 Perfecto). If you order 2 24" hoods you will have to cut the glass to make them fit. In the end, it is cheaper just to order the 48" set.