Add some fresh water to get your SG around 1.025-1.026. Once you get it there make a note of the water level and top off with FW when needed to that line. Then just make your WC water to match your SG. Also, your pH is a little on the low end but pH should work itself out in a tank that size. Just keep an eye on it when you do your first few water changes. Are you using RO water or tap water? Use RO if you can.
If you want to do a reef tank you might want to look into upgrading your light to a power compact, T5 or metal halide. If you go the halide route you might consider a pendent halide fixture or a JBJ Viper style light due to the size of your tank. These are easy to raise and lower. It really just depends on the types of corals you want to keep. Some shrooms and zoanthids might be ok with the light you have but the colors probably won't pop. If you are going with fish only, the light you have is pefectly fine. Great start!
