Then, convection volume will be increased stepwise by successively optimizing the three most important determining factors. First, treatment time will be increased to 4 h, if possible. Second, blood flow will be increased by 50 mL/min per treatment until a value 400 mL/min is reached, provided that pre-specified safety limits are respected. Third, filtration fraction will be increased by 2% per treatment up to a maximum of 33% or the maximally achieved value within safety limits. To take into account different settings between the various dialysis machines used by the participating centers, an easy-to-use conversion table will be provided to the nursing staff, allowing to find the parameter (substitution flow, substitution volume or substitution ratio) corresponding to the desired filtration fraction.