I wouldn't use any glue on a
tank. It's just not worth the risk of possible contamination. If you can't find replacement parts, I would replace the
device.
^ This x1000
Liquid acrylics, glues and other adhesives all contain chemicals, in fact that's their main composition. I know some claim to be safe but you have to remember these are companies trying to sell you their product. My advice better safe than sorry it's just a mod, buy a new one or reach out to the company that made it they might be able to ship you something.
PS: Silicone gasket sealer aka aquarium sealant is toxic enough to warrant a warning on the label telling you not to breath the substance in until it air dries, it might be fish safe if you get the right one (the ones that don't inhibits mildews like the Momentive RTV108 clear gel) but I sure as hell wouldn't want that stuff to come in contact with my
juice, it's just not worth it.