I have a question and an observation/question for the chemistry experts on this forum.

First, my question: What is the powder that's left over after bleach evaporates? Is it salt? Whatever it is, if you mix it back with water, it won't make bleach again will it?

Next, it has been my observation that running somewhat higher CYA levels does NOT increase the amount of maintenance chlorine that you need to add. Yes, you will need more to get the initial level higher or to shock. But, once you have the higher level, it takes the SAME AMOUNT to maintain that higher level as it would to maintain the lower level that you would have had, had you been running lower CYA levels. Are my observations correct?