Last weekend I really dived into the dinoflagellate identification I had planned. Earlier I had contacted 5 dino experts asking for help, but none of them even bothered to reply.
This left me with the difficult task of doing my best and after two days of comparing videos, images and reading through descriptions of various dino species I concluded I've got
Ostreopsis.
O. heptagona fitted the videos and images perfectly and the discription the best, but
O. Ovata came in close second.
This excellent source by Dr. Maria A. Faust was the most valuable information along with various articles, videos and images on the web.
http://botany.si.edu/references/dinoflag/
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I also researched the health issues on humans associated with these toxins.
They are real and I strongly advise in reading up before anything else.
In the case of Ostreopsis there is bound to be palytoxin in the water column.