Base sodium of the dialysate

We used 2008 tea machines. The dialysate acid make sure that we use says that the base sodium for our dialysate is 137. I understand the machine mix is 45 parts water one part Acid in one part bicarb. I understood from my biomedical technician that due to this mixture the minimum sodium level that can be achieved with his dialysate is 137. The machine is not able to add extra water to bring the dialysate sodium level down is it? Our doctors want to set the bass sodium at 135 although our dialysate says it will only go down to 137. I would think they would need to get new dialysate that did go down to 135. Because I don’t think the machine can take it down to 135.That would be dangerous in my opinion. It would also mess with the prescription of the dialysate. We are having this discussion at work and I really need some help with this. Thank you so much