How Often Shall I Clean My External Filter?

[craigybaby37]

just after some advice on how often to clean my external filter.

Its a fluval 105 running bagged carbon, phosphate remover and the rest live rock. And the tank is a uk 20 gallon

 

[chrissaysyes]

I clean my 205 weekly.

 

[yorkcoparamedic]

I clean my 205 every other week and use LR rubble, Purigen, and SeaGel in the canisters.