There are different solutions that can be used during dialysis. They are called dialysate baths. A 2 K+ (or 2 potassium) bath will take more potassium out of your blood than a 3 K+ bath because there is less potassium in the solution and that makes the concentration lower so it will pull more potassium out of your blood. There are also different levels of calcium in the dialysate baths. If you tend to run a lower potassium level in your blood, the doctor may want you to be on a 3 potassium bath so that your potassium doesn't go too low at the end of a treatment. A low potassium is just as bad as a high potassium. The same thing goes for calcium. Most units have a 2.0 calcium and a 2.5 calcium bath.You can tell what bath you are on by looking at the jug on your machine. It should be clearly marked on the jug. These baths are checked and double checked in our unit, and I would imagine in your unit as well.Hope this helps.