Hardware store bleach and ammonia come in many different concentrations for different uses, bleach and ammonia specifically do not mess with, it is an exothermic reaction that puts out poisonous caustic gas and people have died from mixing these two at cleaning chemical strengths. "The concentration available to consumers" is a super dangerous generalization, fairly high concentrations are available for diluting at home or for pool treatments. You can absolutely make incredibly dangerous compounds by mixing things from the pool chemical aisle.