Question: After removing old paint from the concrete surface of a pool, how should you then clean the surface off?

  Options: 
 A. Clean it twice. First with an acid wash mixture of 5% water and 95% muriatic acid, followed by tri-sodium phosphate (TSP) to neutralize the acid and remove dense areas of oil or grease. Rinse it completely with pool water.
 B. Clean it twice. First with an acid wash mixture of 50% water and 50% muriatic acid, followed by tri-sodium phosphate (TSP) to neutralize the acid and remove dense areas of oil or grease. Rinse it completely with fresh water.
Answer: B