The water to a greywater treatment system excludes the black water. This means that greywater contains only 60 % of the total organic matter in standard sewage water. For this reason, the grey water system can be built smaller than a standard wastewater system. In terms of bacteria needed to degrade the organic matter, you only need 60 % of the standard system. Since the bacteria in a BioKube system are bound to the BioBlocks, this equals fewer BioBlocks. If you compare the amount of BioBlocks in the grey water system to a standard Pluto on the right, you can see the reduction in amount of BioBlocks.