One of the functions of dialysis is to correct electrolyte abnormalities which occur with renal failure, such as variations in potassium and bicarbonate levels, which are linked to important clinical outcomes for patients. Metabolic acidosis, reflected by falling bicarbonate levels, is a frequent event in haemodialysis patients and its correction is one of the goals of effective dialysis. Bicarbonate replacement is routinely delivered during each dialysis session thrice weekly with the use of high dialysate bicarbonate. However, local and national data show that over 50% of patients fail to meet a bicarbonate level within the normal range before each dialysis session. Low predialysis bicarbonate levels of less than 22mmols/L have been linked with increased all-cause mortality in haemodialysis patients.