you take out the charcoal bags too. You could probably just never use charcoal again, I was reluctant to switch but it's been 6 months and my tanks are healthier than ever. I recomend it.
Also, tips for maintenancing the
canister filter.
1. Shut it off
2. Close the ball valves and disconnect the unions
3. Put the canister on the rim of the tank and open the bottom valve to release pressure (water will come out so put the hose over the tank water)
4. open the top valve to relieve the vacuum and drain the canister.
5. Close only the bottom valve to stop any residual leakage. Keeping the top valve open will allow you to remove the lid more easily by breaking the vacuum.
6. Put it on the floor and maintenance as normal, there's no more water except what clings to the media.
I like to pour the bacteria substrate into a bucket of tank water. It cleans off the gunk without killing the bacteria.