Please remember to change your filter cartriges regularly. I forgot to change mine once and My filter started to have lots of trouble and water was flowing out the back, I didn't know why untill I pulled the cartridge. It was caked with disgusting green stuffs, water could barley pass through it. I put a new one in and it worked great. Don't forget!!!

Another trick is to rinse them weekly in the tank water removed for water changes. This will allow them to last much longer and preserve the colony of biobugs that is lost when starting with a new filter.

unless you want the carbon to work, then you should change it like every 2 weeks.. (thats what Im doin! @_@ thank gowd fo a bio-wheel!)