using old water

So I have some RO/DI water that was made before I needed it but then it was stored in a trash can. It smells odd now so I’m assuming I can’t use it but someone suggested asking if there was a way I could “clean” it. This seems far fetched to me, but I’ll humor them. It would be nice to not have...

I know that there are multiple write ups on using old tank water but I would very much appreciate situation specific advice if you folks don’t mind. I’m moving my 2’ tessalata eel from his current 55 long holding tank to a 90 gal 4’ x 2’ x 18” (L x W x H) with sump (sump is about 25 gallons)...