Baking soda is fine but you should mix in some washing soda at a ratio of 3:1 or something like that. For the cost of a powder ($20-30 which lasts me months) I've never bothered with baking soda/washing soda. Well, that, and the fact that the washing soda I've seen here has this sort of lemony zesty scent. I don't know what that is, but I'm not putting it in my tank. You can bake baking soda in the oven though to make your own washing soda.
