Are the zoas covered in algae? I’ve cleaned up zoas in a 3% hydrogen peroxide dip with good success.
Also, if they remain closed you should find a friend or store to “babysit” your corals.
Get your tank in check (turn the lights off. Add lots of bacteria, add live rock, and keep your nutrients up.)
My newest and most successful tank ran 20ppm nitrate for the first 2 months, and now I run around 10ppm. You may be worried about algae, but a good CUC and a refugium can seriously bring algae down to healthy levels. It may grow a bit in some spots, but nothing to draw attention away from your fish and corals.
If this is Your first tank, you are not alone! My first tank was a disaster. I couldn’t keep corals opened longer than a week. Somthing was always happening for them to be Upset.
I suspect that there has to be some kind of parameter or bacteria we cannot test for that is what makes a tank “established.” Because in my experience, a dry rock tank with perfect parameters does not equal amazing coral health.
My final .02 cents is add bacteria from many sources, add live rock, keep nutrients up, and start a refugium. You can even set up a HOB refugium for pretty cheap (check Craigslist for old aquarium filters, pop an amazon plant light on it and boom you’ve got an algae farm.)