Not to micromanage / armchair quarterback your tank, but just calling out that a 7.1-7.8 alk change from a one time dose over 15 minutes is in big alk swing territory. Every tank is different, but swings like that caused me major euphylia polyp bailout and dead torches. Other things were probably going on in my tank at the time, but if you're having issues I'd really be careful about changes like that.
Have you been spot feeding them, with mysis sized stuff not reef roids. It might sound repetitive, but the basics like water changes + spot feeding can go really far with less chances for craziness.
Good to hear it at least appeared things improved.
What would be a safe daily increase in alk?
I've never directly feed the hammers with mysis. Just brodcast feed the tank for the fish. I have done it with reef roids/ benepets but not recently. The fish don't let the corals get any food they pick it from any of the corals beyond duncans, nems, and mushrooms that have tend to have a faster feeding response. Any tips on this? I would be willing to try spot feeding the hammers if it could work and I could keep fish and crabs away long enough.