Hi everyone, I have multiple questions because i want to change over my fresh water to a saltwater tank. First I will name off the things that I have. I have a 55 gallon tank with a coralife light fixture with two 50/50 lights in it, I have sand on the bottom of the tank, I have a canister filter, a power head, heater, thermometer, and air bubbler on the back. My question is what else would I need to change this over to saltwater? From what I have read I need Salt, a hydrometer, and coral, and obviously fish too. I was told that I need a protein skimmer and I also was told by a friend who has a saltwater and does not have a protein skimmer and her tanks are fine. Any help would be appreciated.