Thanks, seachange, Actually got some sleep last night as the itching is a little less today in most spots. I have to disagree with the problem being "algae bloom". The only places I was stung were areas covered by my bathing suit; something was trapped and re-acted.we snorkled at Hol Chan last Thursday, and I was in the water in the shallows all day Friday (it was calm and very hot). Seems like most people affected have been in those 2 situations. I have to say, I'd definitely risk stings and plunge in rather than swim in the pool; I'll just be more aware next time and travel with Windex!