Study Rationale - This study will provide high quality evidence from a mulit-center randomised controlled trial about the comparative effects of different targets for CRRT dose in patients with ARF treated in the Australasian intensive care setting. This evidence will have direct relevance to decisions about the care of critically ill patients admitted to intensive care units in Australia and New Zealand. If this study confirms the treatment effect reported in the Lancet study, augmented dose CRRT is likely too become the standard of treatment, saving 250-300 lives/year in Australia and 15,000 lives/year worldwide.