Upgrade not ready yet and DT skimmer quit!

[MitchM]

Your nutrients are going to accumulate regardless if all you do is try to replace that skimmer.
I would cut the supply and return pipes, clamp on some flexible hose and set up a rubbermaid tub as a new sump, totally bypassing that existing tiny sump.
Trying to move a tank with nutrient and GHA issues will cause a lot of headaches when you move up to your next larger tank.