I have both and am confused by your question. The 350's tube doesn't fit as far as I know but I haven't tried it.
The H.O.T. is a canister filter already but if you mean you want to remove the plastic container that you keep media like AC
in you can do that and just keep the tube and top plastic piece in for filtration without the media container. You do that already if swapping out the media container for the micron filter sleeve and it runs fine with just the tube but keep the top plastic piece on to hold it in place.