As far as lights I have Steve's LED's and have been very happy with them. I don't have a skimmer on my 12g because water changes keep it clean. As far as other tests, you need calcium, magnesium, alkalinity, phosphates, and either a hydrometer or refractometer to test for salinity. Calcium is an essential part of coral growth. Calcium, magnesium and alkalinity are key to keep in balance in your tank. Let me see if I can find a link for you.