I'm amazed you could get such fast speeds with ISO100
And great idea with the flash, I might try that sometime
What? He is using an external flash, and when doing so, you always put it at ISO 100 because of the available light coming from the flash...
Have you actually tried photographing water droplets in mid-air? Even with a lot of available light you need a very quick shutter timer.
DVS you mistaked ISO for shutterspeed
Not really, faster shutter speed = less light = higher iso or aperture required.