[soapy]

If you are certain it is your tank causing this issue, you could be allergic to salt water I suppose or you could be allergic to one of the corals in the tank.

Do you run carbon? Carbon can be a great help in removing coral toxins from the water.

Some of those corals can be incredibly toxic. Perhaps it would be a good idea to remove some of the more likely suspects. I am thinking the zoas, palys, and toadstools. Maybe some of the other softies too. With luck you will pull the offending coral. It could even be a hard coral.

Unfortunately there is also the possibility that a bacteria, algae or sponge in the tank could also be the culprit. There is so much unknown stuff going on in our tanks that it will be pretty hard to pinpoint the cause.