Just off the top of my head, haven't given this much thought. Could you salt the hash with something way less predictable that gets discarded when the next one

Just off the top of my head, haven't given this much thought. Could you salt the hash with something way less predictable that gets discarded when the next one is generated? Assuming you only kept logs for a day for example you could regenerate it daily and store $salt somewhere only the most senior of senior techs can access it (if anyone at all)