Pebble Tec is a company that makes pool finishes out of pebbles fused together to create textured pool surfaces. One of Pebble Tec's finishes is called "Pebble Sheen," which is a smoother, shinier version of their original finish. Like any pool finish, Pebble Tec finishes are susceptible to stains from algae blooms. Vinegar is an affordable, effective stain remover that is safe to use on just about any pool surface, including those made by Pebble Tec.
Drain your pool as you normally would. Vinegar will affect your water's pH level and pool water will interfere with the cleaning process, so it is better to start with fresh water once the algae stains are gone.
Pour either apple cider vinegar or white vinegar into a spray bottle. Both types are equally effective against algae stains, so use whichever you have on hand. Add about 1 tbsp of liquid dish soap to the vinegar and shake the bottle until the soap dissolves.
Mist the Pebble Sheen walls with the vinegar and soap solution. Wait about 10 minutes and spray the walls again.
Use a pool brush to scrub the Pebble Sheen walls. The bristles will get into the little grooves between the pebbles. Spray more solution to work up a good lather with the vinegar and scrub until the algae stains are gone.
Rinse the walls of the pool with a hose and drain the pool of the vinegar and water. Keep rinsing the walls until the water runs clear. Refill the pool and balance the chemicals as you normally would.
Use a solution of one part bleach to four parts water as an alternative to vinegar.