Hi, It seems to be avery common problem with aquarius machines,
tip the machine on its side and disconnect the pump, (remove water pipes and then little connection) you'll need allen keys and set of philips screwdrivers also
disassemblwe the pump if you're brave enough and clean it and check it for obstructions/blockages (found it quite easy)
then reconnect it up to machine and away you go...worked forme-machine running like new
Dave
Dave
June 2008