You should add live rock now whether you put corals on top of them or not, they are an important part of a naturally filtered tank (this means easy for you to maintain, better for the fish, etc.).
A refugium is a type of filtration that uses macroalgae to remove nitrate and phosphate so that it is not available for bad algae in the tank. It is usually a section in the sump that has a light over it so that the macroalgae (usually chaetomorpha) can grow.
A protein skimmer is a type of filter/equipment for saltwater tanks. They can go in-sump, hang-on-back (HOB
), or external.
You would need to buy either distilled water or buy water from an aquarium store. RO
drinking water is not pure enough.
is not cheap. You can cut costs by getting good deals on craigslist or local clubs, but it is not something you can cut corners on without your tank suffering. The good thing is that if you setup a sw
tank properly it will be even less maintenance than a fw