you can use regular white sugar but it’s best to use organic sugar. Your water kefir grains will be a lot happier with the organic stuff. It’s also not a bad idea to add 1/8 teaspoon of molasses for added minerals.
I’ve used reg white sugar if I haven’t had a chance to pick up any organic sugar.
Btw don’t worry about the sugar content, most of it will be gone after the kefir eats the sugar.