Those pics help, agree that's TN. Two things stand out to me, low light and high nutrients will cause this. If you're going to keep higher nutrients, then you better crank the lights and flow to match. But that is oversimplifying a bit. A couple of things that you can do slowly that will help in the long run. First, slowly bring down PO4 and alk (8-8.5) and slowly turn up your lights. Certain bacteria will help, I like using PNS Probio for reducing PO4, but I would use half the recommended amount until you get to 0.1ppm of PO4. When increasing lighting, you need to increase flow to help the sps in removing waste and provide o2. If you're not using macro algae on a reverse light cycle, then I would seriously consider setting something up. Just curious, but did you start this tank with dry rock?