After reading http://www.dizziness-and-balance.com/disorders/menieres/hydrops.html , it makes me wonder whether there was MSG in the food we ate last Saturday. It seems to indicate that this may be a trigger, 'tho it seems unlikely that a migraine-like condition would exist for days. In any case, keeping sodium levels are a set level seems to be one way to control the problem. Same for caffeine. (Note that it isn't an issue with overall sodium or caffeine levels, but rather just keeping them constant.)