Tony,
I've been to the Dead Sea twice, once for a week and then the last time, a month. I actually got a really painful sunburnt-type rash from the sea and when I went to see my doctor out there he told me that my skin was sensitive to the salt(!) so I would say that floatation tanks aren't the answer unfortunately.
The guy's saying it stings broken skin, well if you've been to the Dead Sea that's painful. I used to scratch (habit more than feeling itchy!) before wading in and boy did I regret it. Also shaving didn't help! So have a think about what Epsom Salts would do. I think the whole floating in a dark room is really de-stressing but the sting would stress too too much!