It's tough to find a 50 meter pool this time of year in this area. Cal Lutheran has a 50 meter pool but it is not set-up 50m in the Fall/Winter. Simi's pool is generally not 50m, but is (I think) for the Conejo Valley Multisport Masters morning workouts, from 5:30 to 6:30 AM. Other than Van Nuys, that's probably your only option. CVMM's webpage is here:
https://www.conejovalleymultisportmasters.com/index.cfm; calendar is linked there. You can do a free trial workout. Send an email to the owner, Nancy, especially if you're there for the Thanksgiving weekend since the holiday schedule may be different than what's posted.