The Fluval U3 internal filter is suitale for aquariums up to from 90 L to 150 L. The U series underwater filters have a three stage filtration which is ideal for use in fresh, marine or reptile environments. Stage 1 foam removes large particles, Stage 2 poly/carbon cartridge traps fine debris, improves water clarity and removes impurities and then Stage 3 BIOMAX provides optimal biological filtration efficiency. The Fluval U series range are ideal as supplemental or stand-alone filters, silent, efficient, simple to install and easy to maintain. Flow rate 600 litres per hour.