Hi and welcome to TRT!!!
The best thing you can do is decide on a specific type of coral or enironment you want to emulate in your tank. If you decide you want a mixed reef with SPS coral included you will need
metal halide lighting. Clams and most anenomes also require some strong light.
For filtration all you need is LR (live rock) and a protien skimmer. You will hear all kinds of "rule of thumb" on the amount of rock but I would say from 3/4 lb per gallon and up. The rock houses bacteria that will provide all the
biological filtration you need. The skimmer will remove disolved solids. Pay for a quality skimmer like Euroreef, MRC (my choice) ASM or another reputable name. The skimmer is extremely important and many people try to save money only to spend more later on a good one.
Research what you want in the tank before you spend any more money and ask questions here before you buy! Post in the "General Reef Discusion" for most exposure and fast response.
You will have tone of questions come up as you learn more, ask away!
Robert
