If I may ask...what type of carbon were you running before you pulled it?
If it was ROX, then this could be the culprit. In my last tank, I was dosing vodka and when I introduced ROX, SPS slowly receded from the base. I was trying to see just how low I could get my nitrate and phosphates, and in the end it bit me in the $%@. Running so close to nutrient deprivation really leaves little margin for error. You have to ask yourself if you really need carbon dosing. Not everyone does, and apparently you may be one of them. I know that it's all the rage, but I've since stopped and couldn't be happier. While vodka/vinegar dosing, things look like they're doing great while nutrients are dropping, but once you are truly undetectable things seem to go pale, and if alkalinity is too high, they tend to recede from the base up.
Furthermore, I'm not sold on vodka dosing being a great phosphate control method. Many people who have 0 nitrates while dosing vodka have gotten hair algae outbreaks...and I'm one of them. Some of the nicest tanks I've seen keep their nitrates measurable (and below 5) while concentrating on phosphate. In the end, I found that having a proper stocking of fish, and feeding those select fish well is much better and safer than the adage you hear from many vodka dosers saying you can feed more and get more fish. Many vodka dosing tanks have cyano outbreaks throughout the year that have to contended with, and then it just becomes a cycle until the next cyano outbreak. Again, I think it can be done, but it's much more work than it's cracked up to be.
I hope things are on the mend for you.
