Some people have had luck doing it in 2 portions like you did but from a logical point of view knowing that digestion starts in the mouth and that tells the system what to expect and it reading all that initial salinity in the initial dose. I don't know how it might adjust and how it will mix once inside the system cause that first batch did mix with gastric juices and when you chase it down to make it the formula ratio can the system interpolate all that as one single mix that is the same specific gravity of blood so then it won't get absorbed and pass through the system and work it's rinse mojo mmmmmmmm....................
The other thing I meant to ask and this is a very common mistake. You did measure out 2 TEAspoons of the salt and not 2 TABLEspoons right?