Until you get your phosphate up you're going to have issues. I had same problems as you at 4 months. My nitrate and phosphate bottomed out. Once I got those numbers up the tank cleared and corals were very happy. I clean glass once a week now. At almost 9 months, have moderate GHA but good cleaner crew and coraline forming so it should out compete the GHA. At 4 months your tank is not to bad at all. Try and stabilize those numbers and avoid dumping chemicals in to fix everything. It just throws off all balance.