We recently stayed at the Riu Negril, but used the beach at the RMB. One partivular day, we were floating in the water, on our water hammocks, and started feeling burning sensations on our backs, arms, legs etc at separate times. We didn't see anything in the water and weren't sure what was happening. The burning sensation would last approx 10 - 15 min at each area and go away and not leave a mark. Does anyone have any idea what could have caused this? Could it be baby jellyfish or are they visible in the water? We have been traveling in the caribbean and mexico for about 10 years now and never experienced this. It only happened one day after a night of thunderstorms. thanks!