Home haemodialysis (HD) is a common and relatively inexpensive form of dialysis in New Zealand that generally provides good quality of life. However, survival is still poor compared to the general population and 67% of patients die from cardiovascular disease. The SOLID Trial evaluates a cost-free intervention that would potentially improve these patients' cardiovascular outcomes. The intervention involves reducing salt administration during routine dialysis. Earlier research in South Auckland showed that this simple measure reduces blood pressure. The SOLID Trial tests whether this measure also improves cardiac structure and function, since this would in turn reduce the risk of sudden cardiac death. If the intervention works, it would become the standard practice both locally and globally, and improve survival for all dialysis patients but especially those undergoing home HD. Remarkably, the intervention may be one of the few in medicine to provide health benefits at no added cost.