GLB 71434 20.2 lb GLB Longevity Tablets. GLB® sanitizers ensure your swimming pool’s water is clean and as safe as can be for swimming. Our range of granular and tablet products eliminate harmful contaminants that can cause illness for swimmers and, as an added bonus, help to keep algae at bay. These proprietary, slow-dissolving Cal Hypo tablets can be used in the GLB® Longevity Feeder, GLB® Longevity Floater (coming soon!) or added directly into the skimmer.