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.
With sole legal custody, one parent has the sole right to make all of the legal decisions regarding the child. This includes any decisions regarding religion, education, general health, medical treatments, general welfare and education. This type of child custody is not commonly given anymore.