Things You'll Need
Tile brush and soap
Grout saw or power tool
Hydrogen peroxide or bleach
Algae could leave green, pink, yellow or even black spots on your pool grout and tiles. Getting rid of the algae is important because it is likely causing damage to your filter, as well as leaving unsightly colors on your pool's walls.
When removing grout, always wear a protective breathing mask.
How to Regrout a Swimming Pool. Tile is easy on the feet, and beautiful, and it also retains its color longer than other pool surfaces. The grout that holds that tile in place, however, can become grimy, dirty and cracked. Replacing the grout is a time- and labor-intensive job, but doing it right will ensure several more years of easy swimming pool maintenance.
Check to See If You Need to Regrout
Brush your tile and grout with a tile brush and tile soap before you regrout the pool. The grout and tile might have calcium or other minerals built up on its surface, which can cause discoloration. Discolored grout does not necessarily mean you need to undergo the intensive task of regrouting.
Add an algaecide to your pool water and ensure a proper pH level if you have algae growth in your pool. Be aware that stubborn black algae growing in your tile grout will be very difficult to remove, and it means that you will probably need to regrout.
Mix a water and a hydrogen peroxide solution in a 2:1 ratio (2 parts water, 1 part hydrogen peroxide). Spray this solution onto exposed, discolored grout. Use bleach to remove stubborn stains.
Use a grout saw to cut into the grout. For large jobs, consider using a power tool with a carbonite or diamond blade to cut through the grout.
Use a grout scraper to remove the remainder of the grout from between your tiles. Alternatively, for small areas, you can use a chisel, but this will be more labor-intensive and less precise.
Clean out the area between the tiles by using a mixture of 1 cup white vinegar and 1 cup water.
Vacuum up any grout pieces and dust.
Choose a waterproof epoxy grout made for swimming pools and high-humidity areas.
Choose a grout color that matches the old grout, or if you're replacing all the grout, select a color that matches your tiles.
Mix the grout as stated on the container, then spread it evenly using a grout float. Make sure the grout completely fills the joint between tiles.
Work in small areas and quickly mop up loosened grout from the tiles with a damp cloth.
Wait for the grout to dry.
Seal the grout with a sealant designed for use in swimming pools. This will ensure that the grout stays solid for several years.