Usually I get generic bleach at Publix. The label says it contains Sodium hydrochlorite and "other materials". It works fine.
Sometimes when they are sold out of the generic bleach we get Clorox concentrated bleach. The label says it contains Sodium hydrochlorite and sodium hydroxide. It makes bubbles on the surface of the pool. The bubbles go away in a few minutes, and it is not a problem, but I wonder what the extra ingredient - sodium hydroxide - is. Is it making the bubbles, and is it causing any other problem?