I would recommend doing a couple of water changes to my the calcium down. I'm not sure what kinds of coral you have, i wouldn't advise buying more coral until your parameters improve. As far as phosphate control there are several options, feed quality frozen food but not in excess, you could add a refugium with macro algae, you could use gfo in a reactor, phoshaurd in a reactor, really it's hard to say what would work for you. For myself i rely on a refugium and a small amount of gfo, i prefer to have only a refugium but it needs to be bigger to be able to use up more phosphate.
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