It also seems to make clear that the type of potassium salt you are taking (chloride, citrate, gluconate, acetate, bicarbonate, etc) does not matter. The only thing that counts is the amount of actual (elemental) potassium you are ingesting.
Legal custody of a child means having the right and the obligation to make decisions about a child's upbringing. A parent with legal custody can make decisions about the child's schooling, religious upbringing and medical care, for example. In many states, courts regularly award joint legal custody, which means that the decision making is shared by both parents.
Having legal custody of your children means that you are responsible for making decisions about the important things in their lives, like where they go to school, what religious instruction they receive, whether they need academic tutoring or psychological counseling, and when they go to the doctor.