SenGuard Permanent Marble & Granite Sealer and Daltile® PROADVANCED™ 15-year Sealer are two products recommended by professionals for taking care of granite countertops. Applying sealant to stone countertops increases the time it takes for a stain to set, saving even hard stones like granite from unsightly blemishes.
SenGuard Permanent Marble & Granite Sealer is a product that uses advanced nano-technology to form a stain-repelling barrier, according to Dallas-based Countertop Specialty that also recommends Stone Care sealants for granite slabs. Daltile® PROADVANCED™ 15-year Sealer, recommended by HGTV-featured company Precision Stone Works, is a product that claims to protect counters for the next decade.
Countertop Specialty suggests performing a lemon juice and oil test, or water drop test, to determine how porous the granite counter is and whether the countertop needs a new coat of sealant.