I use this product, http://www.fosterandsmithaquatics.com/product/prod_display.cfm?pcatid=5016, I add a few drops (comes with a mini turkey baster, sorry don't know the name for it) to the frozen food as I defrost it. It comes in a smell proof container, but hits you in the face when you open it.
All New Life Spectrum formulas contain garlic, the TherA formula contains more of a mega dose. In the case of NLS, garlic is added for its natural anti-parasistic/anti-bacterial properties.