I'm trying to cultivate a sourdough starter for the first time. I'm following the instructions here: http://www.kingarthurflour.com/recipes/sourdough-starter-recipe
My starter is about two weeks old now, and I'm getting worried. It has yet to show much activity at all. I usually just see a few small bubbles on the surface. The bubbles haven't gotten any larger in size, and there hasn't been any noticeable rising either. There is a nice, mild sour smell to it though. Oh, and occasionally there is a small amount of hooch. Of note, I did deviate from the recipe above after about a week, when I read online that feeding the starter twice a day might be too often. Changing the feedings to once a day did not seem to make much difference. I've attached a picture which I hope is clear enough to show how my starter looks. What should I do?