Believe it or not but all these companies are essentially using the same mineral salts as one another, they're just packaging them a little differently. So as long as you're comparing inorganic bottles to inorganic bottles, the only real difference is the actual balance of minerals they are providing. So for example, if AN and Fox Farms were selling the same 5-5-5 all purpose plant food, you could expect identical performance. Makes sense? So shop based on your NPK needs rather than focusing on brands.