You might continue running your HOB for a month or so in conjunction with your filter. That would insure your cycle. Then, you can transfer your old media into your canister if you want and just continue with the canister.
I’m moving the aquarium to a new position. The 5 inches the HOB takes is critical so I would like to detach the HOB as soon as possible. If I put the media filter and the sponge in my Canister, could I️ eliminate the need to run both filters simultaneously
Well, you didn't SAY that! I would move all media to the new canister. I would probably buy some TSS+ or Stability, though. When I started up my canister on my new aquarium, I had seeded a couple of bags of media in one of my tanks for probably 2 months. I still didn't have a cycle on my tank and ended up using TSS+ to help obtain a cycle on my aquarium. Hopefully, since you're just changing the filter (mine was a brand new tank and canister), you won't have as much of an issue.
I believe it will and have just done it. As said the best way is too leave the hob and canister running together for a month or so. Can you but the hob on the side of the tank. Like I said I just did this. But I took about two weeks to move all my fish. I moved a few at a time to give the bb time to grow.
Just move the biomedia from the HOB to the canister. It's what I did and I never had a recycle or ammonia spike. If you think about it its just like taking the biomedia out and then putting it back in the HOb again, except your putting it in the canister. I love my canister so much. Never going back to HOB's.