I would test everything alk, ca, mag, no3, po4 low range, ammonia, nitrites, check for copper, recalibrate your refractometer. Do not put hydrogen peroxide in your tank! Check for pests, red bugs and AEFW. If you are running a Ca reactor check for alk spikes and check that you ph is in range. Are you running bio pellets your vodka? If so stop they strip the water to clean. A few of the corals you pulled out could have been fragged and saved.