+1^ mecheng
The iodide may be useful on some bacterial pathogens plus bugs. The cocktail or multipronhed approach works best in tough cases IME.
If possible I like to directly apply full strength 3% peroxide to exposed skeleton carefully with a pipette, brush or swab. I'll let it flow just underneath the margins of the tissue, but a avoiding the bulk of the polyps. Sometimes I cut the peroxide to RO 1:2 or 1:3. I will rinse in tank SW and let it sit 5-7 minutes.
In 2 instances I followed this with an antifungal medication just as described above on scolymias, rinse in SW, followed by the exact same procedure with a few drops of Seachem's iodide dip & SW dip. In one case all the tissue regrew over the exposed skeleton. Good as new. In the other, all recession stopped, the scoly regrouped to about 1/3 it's size, but looks great, regrew or retained its mouth & it eats and is growing again. I elevated both off the sand bed 1/2" and they've been good ever since. This works with most LPS, but can't imagine it working with SPS like acros however. But it sure sacked whatever the problem was (I always assumed bacterial rather than animal pests but was never certain.