Who else would ask a smart question like that?
This was the question Bill Gates asked Tobi after he had finished his snorkeling trip through Silfra on the walk back to the car park.
Wow, one of the best questions I had in over 1000 dives in Silfra, Tobi thought... but not quite sure about the answer.
"I think it´s first of all because there are so few particles in the water..."
Then David commented from behind "Well, no, a few years ago we had scientists here who examined the water and found that the Silfra water had much less dissolved elements than a bottle of shop-bought drinking water".