I'm not really sure what happened, but about 2 weeks before making the lighting switch I noticed a concerning change in many of my SPS corals. The skin started bubbling! After doing a lot of reading online, it seems that it's a relatively common problem, but nobody can come to a consensus on what causes it. Some people reported that the bubbling corresponded with low salinity, low magnesium, high magnesium, carbon dosing, and the list goes on. I did find more than a couple references to carbon dosing, however, and the skin bubbles did appear around the same time as I had bumped up my dose and was beginning to experience bacterial blooms in the form of stringy colonies all over my rockwork, so I decided to eliminate one thing at a time and back off the vinegar dosing.
I first backed off by maybe 20 ml, then another 20 ml several days later, and then some more - until the stringy colonies disappeared. The skin bubbles remained, so I decided to cease dosing vinegar altogether last week. The skin on most of my SPS is beginning to settle back down to normal, but still not there yet. Some corals seem unaffected by the bubbles, but the bubbles have definitely had an adverse effect on several pieces. My candlelight acro swelled up like a toasted marshmallow, and several of those bubbles have popped - exposing skeleton. It's bizarre though, the skeleton hasn't been exposed in the same manner as if tissue necrosis had occurred, there is still colour there... but I can see the outline of the corralite structure. It seems that the tissue stuck to the skeleton after it popped and is mostly reattaching and growing.
Like I said above, I have no idea what happened. Whether it was the vinegar dosing - or if something got into my tank - all I can do is exercise my patience, sit back, and see what happens. Have continued my regular water changes, except changing a little bit more than I normally would, and stopped the vinegar dosing. I don't believe the lighting change has had any effect, as the bubbling was already at it's worst when I installed the halides. So there's nothing else I can really do.... that I can think of!
Anyways just thought I'd share that experience with you guys. One week things can be going great, and the next week BAM - problem. My corals were looking healthier than ever and growing at a steady pace just over a month ago, and now I'm praying for recovery.
