The Portland cement-based tile grouts used today come in two forms: sanded and non-sanded. Grout joints that are 1/16 inch and smaller, (like wall tile), are basically cement mixed with certain additives to give it the needed characteristics to perform well in a smaller grout joint. Sanded grout is just plain grout to which sand has been added for strength and is preferable for joints larger than 1/16 inch. Grout joints from 1/4 inch to 1/2 inch may have even larger grains of sand in the grout to accommodate the strength needed for the differing joint widths.
For the smaller tile grout joints use the Grout Getter with the diamond blade for grout removal, as this has a smaller radius at the point and can dig deeper into non-sanded grout joints.
Sanded grout joints are typically 1/8 inch or larger. The triangle blade Grout Getter is best suited for working on these wider joints.