nirtate

Is my tank too dirty? What do I add for a CUC? I have 3 mexican turbo snails, 4 astrea, 1 nassatrius (idk) snail, I had 1 tiger conch but I haven't seen him in a week. My corals and fish seem happy and my corals are open and growing pretty quickly. Parameters: Alk: 9.2dKH Cal: 400ppm Mg...