I see the picture. That's an HOB (Hang on Back) filter. Canisters will sit under the cabinet and have hoses that go into the tank. I would normally put the carbon on the bottom but since you are going to use meds just go ahead and tank it out. The only HOB filter I've used is for my 5 gal. Someone with more knowledge than me can chime in here if I'm wrong but I would take out the carbon, put a sponge in to catch any debris, then the ceramic rings, (or cork looking things), then another sponge on top to catch any little debris still going through the water in the filter. When you clean the filter, don't rinse off all of it at once. I'd clean one sponge in tank water in a bowl, then leave the other stuff until next time. If you clean it all at once you lose your bb (beneficial bacteria). My sponges get dirty so what I usually do is soak them in a bucket of some of the tank water when I'm cleaning and then put them back in. The next time, I'll leave them and rinse off the ceramic rings with tank water. I understand you aren't suppose to change them with new ones (sponge or rings) until they are falling apart. Then still just replace one or the other. Not both at the same time. Hopefully this will help. I hope it's not too confusing to understand my method. LOL!!