There is little to no important difference. Baking soda is perfectly adequate. Bake the baking soda if you want it to boos tank pH.
Some have borate in them, but I do not recommend those anyway.
Many claim they do magical things to the pH of the water, but really all they have is a ratio of carbonate to bicarbonate that fits a particular pH in seawater. As soon as you add it, the pH will shift away from that ratio.