Tank maintenance filter cleaning

[Giancarlo_Flex]

So I have 2 filters. One has a bio filter and the other just has a bag of rocks with filter floss that I change weekly. Should I change the blue filter? Is that good bacteria or bad?

 

[JC1977]

Toss the Cartridge and replace it periodically with a new one. The sand, rock, and bag of rocks (I assume is bio media of some sort) will hold most of your nitrifying bacteria.