On two occasions, I had these symptoms on multiple corals associated with alk test kits reading high, as I originaly suggested. (API and Salifert in my case. I think old alk test kits in general are unreliable.)
On one occasion I had this problem on a single acro when I moved a large estanblished colony just a few inches, I think it was actually the lighting change although the vertical change was only a few inches - at most. it could have been a little less flow too.
In both cases every coral recoverd, the bases were never quite the same though.
I would think the new Hamiltons may have less punch than the Ushios and that 6 hours may be too short, but I've never used either, so you might ask folks who run Hamiltion 14Ks.
On one occasion I had this problem on a single acro when I moved a large estanblished colony just a few inches, I think it was actually the lighting change although the vertical change was only a few inches - at most. it could have been a little less flow too.
In both cases every coral recoverd, the bases were never quite the same though.
I would think the new Hamiltons may have less punch than the Ushios and that 6 hours may be too short, but I've never used either, so you might ask folks who run Hamiltion 14Ks.
