I'd be concerned about your iodine levels since there isn't an effective way to test for it currently that is available on a hobby level. There is no reason that water changes can't keep up with the iodine needs imo
That aside, when I see any soft coral or polyp have issues I always want to look at the alkalinity. Alk
swings can have a big effect on them and can lead to quick demise at times. I'd invest in a quality alk
test so you can track how the levels are in your system.
The answer to both statement at this time is large water changes. It will ensure everything is in line upon completion.
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