Hello KatMS
Well, for this trip, a Day pass is a bit of an overkill, a one-way half fare ticket would cost you CHF 16, a single and return CHF 32.
Is it a “Day Pass for the Half Fare Card” or a “Saver Day Pass”?
Which amount did you pay for one pass?
When purchasing tickets, I suggest you to use www.sbb.ch/en or the SBB Mobile app on your smartphone. Enter the start and destination point, the booking engine will suggest you the best ticket. As in your case, a point-to-point ticket might be the better deal than a day pass.
We are there for you should you have more questions. Also the agents in the SBB Travel Center can help you find the best tickets for your journey.
Kind regards,
Roland