Hello everyone, I'm brand new to the world of saltwater and I'm wanting to start a setup. I don't really understand exactly everything that is needed to get started. I know you need a tank, stand, live rock, live sand, power heads(not really sure what they do), water, and salt, but filtration is what confuses me. What are skimmers and sump pumps? Are they necessary? Also for my first aquarium I was thinking of doing a 75g setup. Approximately how much is going to cost to get started? I'm sorry if it sounds like I don't know what I'm talking about because really I don't so I was kinda hoping you guys could help me out.