Saltwater overflow switch to Canister

[Petrella88]

So I have a minimal amount of experience with saltwater because I never recreationally got into it but after having started this company I've logged a few hours over the years. So I have a contract with a client for a 90g with an overflow sump set up and the sump box is sinking into the stand because it's about a 25 year old set up. So every year I have to break it down and reinforce the base with plywood because the weight is pulling on the plumbing and I don't think there is much left if anything for me to work with down there from all the Salt creep and rot but the owner of the company doesn't want to get a new stand because it matches his office. So I was thinking about setting up a Canister (probably Filstars X series because that's what the rest of my tanks use) and I was just wondering if that's something I can do or if I need the sump system? Curveball: the tank is a center piece, not against a wall, with a canopy.