I feed my tanks frozen a few times a week to give my fish and inverts a healthy, high quality diet. When I thaw out my frozen I usually add several drops of Garlic Guard. Not only does this seem to help my ADF and corys locate their food more easily, but from my understanding garlic has antiparasitic and immune-system bolstering properties. However, are there any negatives to putting it in my tank multiple times per week? I've gotten into the habit of draining off the liquid on my frozen food after it thaws and I perform a 50% water change weekly.