Diesel? What I would do is fix it and a DIY at that. First, you have to find a place to store the diesel. Two 55 gallon drums that are clean should be $30 tops. Plus they are handy.
Now, to fix the leak. First, you must find the leak. No big problem with the diesel in it to get the area down, to pinpoint the leak, a bit of dye penetrant developer will work great. This is a spray powder that is used to find weld defects using a penetrant dye. The fuel should wet the powder enough to show, even with the tank drained.
Now, remove the external coating (powder coat?) and do another dye penetrant developer check. I bet this was a GMAW aluminum weld which are known for porosity. Once found, you can drill and tap the porosity with a small machine screw thread, sealing with a fuel resistant sealant.