Heat the 1/2 cup of water stovetop and while that is warming put the sugar, sea salt, and ConcenTrace into a quart mason jar. (If you have more than 1/4 cup of water kefir grains, simply double this recipe into a half gallon jar).
Pour the heated water into the jar with the sugar mixture and stir with a wooden spoon to dissolve. (Note that when working with ferments it is advised not to use metal utensils as it can disrupt the environment. I always use wooden tools)
Fill the jar the rest of the way with fresh water, leaving a couple inches of headspace at the top. This is your sugar water! Add your kefir grains to the sugar water and put your lid on.
Let the water kefir ferment at room temperature for 2-3 days. This ferment prefers to be in the dark so I place mine in a kitchen cupboard. A closet works too. The warmer the air temp, the faster your ferment will go so keep the weather in mind especially in the summer. If you live somewhere cold, it may take longer.
After your kefir has fermented to your taste, make another batch of sugar water, strain out the grains and place the grains into the fresh sugar water to ferment again. The fermented water kefir left behind can be consumed right away (I like it with a squeeze of lime or lemon!), or chilled in the fridge to drink later. You can also do a "second ferment" on your finished water kefir to flavor it, creating a bubbly, "soda-like" drink.