Welcome aboard! Now about your question. As stated above already, you MUST have a test kit. Almost as important as the salt and water. Ive noticed nobody has mentioned it, but im curious, what kind of water flow do you have? Any powerheads or is it just from the filter return? This will also determine what kind of corals you can keep. Also, why did you choose to start yoir adventure in reef keeping with a small tank? Space, money, had it sitting around? A 55 gallon tank woulda been a better choice to start with, or bigger. Not to big, not to small.