After months or years of pool use, depending on water chemistry or hardness in your area, the pool perimeter tile may start to show a buildup of scum made up of calcium deposits, algae, or other contaminants. This will usually be evident by either whitish haze on the tile or a dark green ring on the surface of the tile at the water line. Fortunately, the cleanup for this is similar to that for any contaminants that settle on the pool tile at the water line.
For "green" alternatives, use the substitute for the material highlighted by an asterisk below.
Things You'll Need
Stainless steel or nylon pool brush (for algae removal)
Pool pumice stone (for calcium and stain removal)
Respirator with a filter for acid vapor (for difficult projects)
Make the Tile Accessible for Cleaning
First, depending on the water level, you may need to drain down your pool slightly so that all of the perimeter tile is exposed. You can do this by setting your pool pump filter to backwash and letting it drain the water level down to just below the bottom of the tiles. Once the tile is exposed, you are ready to start cleaning the tile. Caution: do not drain the water level too low, as you will need to have water level close to the tile to complete the cleaning.
Start to Clean!
Evaluate the residue. If it looks like algae, try a stainless steel brush (for a cement pool) or a nylon brush (for a vinyl pool) along with a little water, first. If brushing starts to remove it the residue, proceed with cleaning all of the tiles with way. If not, spray a few tiles with vinegar, let sit for a minute before proceeding with the brush.
For hard calcium buildup, try the pumice stone. To prevent scratches, make sure the tile and pumice stone are both wet. Grip the pumice stone firmly and use a back and forth motion to clean the tiles. Experiment on a tile in a less exposed location to make sure it will not damage your particular tiles. (Most ceramic tiles will not show any effect from the use of a pumice stone.)
Calcium deposits from hard water are more difficult to remove and may take more elbow grease and a longer time to clean. Spray 100% vinegar on tile and let it sit for 5 minutes. Clean a few tiles at a time, rinse with pool water, evaluate, and continue. Repeat until all of the pool tiles are clean. Some people may want to get into the pool to do this cleaning, but be careful when doing this if working with pool acid or other tile cleaners.
Difficult Stains or Residue
In some cases, the deposits (such as calcium) are difficult to remove with just a pumice stone and vinegar. You may also need a small amount of pool acid (muriatic acid) that can be brushed on to the stains and then scrubbed with the pool brush. Although this is a weaker acid, it can still cause injury or chemical burns if it gets on your skin or in your eyes, etc. Always wear personal protective equipment (eye goggles and gloves) that are resistant to acids, and a respirator that has a filter for acid vapors. Let the acid sit for a few minutes on the tile, then scrub. The excess acid will flow down into the pool water and should not affect the pool chemistry very much, especially when water is added back into the pool.
Commercial Tile Cleaner Solutions
There are some commercial tile cleaners available. Most are very strong and contain hydrochloric, phosphoric and/or hydrofluoric acids (or a combination). They are very potent. If using one of these types of cleaners, follow the instructions carefully and use full personal protective equipment.
Once the tiles are cleaned to your satisfaction, you may now refill the pool with water to its normal level. Run the pool pump for a few hours and check the chemical balance to make sure it is correct. Rinse any pumice stones left over (they tend to wear down pretty quickly), rinse your pool brush and secure the cap on any acid container, and put them back in storage. If you have pumice residue on the bottom of the pool, now is a good time to vacuum and brush the bottom surface of the pool. If you notice brush bristles have fallen into the pool, it's time for a new brush.
A swimming pool with crystal clear water and attractive, clean pool tiles is a joy to behold! You may want to consider a periodic maintenance cleaning to keep the tiles clean. You may also want to consult with a pool supply store to analyze your water and/or to determine why the tile may be getting residue or contaminants on it in the first place. Regular observation and maintenance of your pool tile surfaces will make the job easier in the long run.