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.
For example, a parent with legal custody can decide where a child should go to school, how the child should be disciplined, and if the child should have a certain religious upbringing. Like physical custody, parents can share legal custody or one parent may have sole legal custody rights.