The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.
I havent ever used that filter but i will assume its 3 stage?
The sponge and bio don't have to be replaced unless they are damaged. Just rinse them in tank water when you do water chnges. Also, if you use carbon that should once a month.