I've had this issue a few times before where I'll have a large bottle of Excel, but over the course of a few months, it will evaporate to way less than it should be, even when I'm dosing it daily. I'd buy smaller bottles, but it's cheaper to buy in bulk, and I think I'll be using it more often than I have been. My solution for now has been to decant it into multiple sealed glass bottles to try and stop the evaporation. Bonus being that these have droppers, so it's easier to dose smaller amounts.
Anyone else have this issue?