I do not know if there is much of a difference. There may be an advantage to having fresh garlic juice made by your own labor. I use Garlic Extreme, I know other hobbyists who use Garlic Guard...and I am sure there are quite a few who don't use garlic at all. The most I have read on it is that we really don't know what it does. It might attract picky fish to eat because the odor is so strong and might be arousing the fishes' curiosity moreso than attracting it to the buffet itself. It might act as a repellant for parasites, much like it can above the waterline. Its active ingredient may bind to damaged areas and have therapeutic effects. Whatever is going on, the use of it has become popular. I use it, but only when I have a fish in QT.
