Olson's time of 24.15 in the 50 freestyle also matched her league-record time from last year.
Olson then teamed up with Katy Campbell, Samantha Campbell and Megan Arnold for another league title in the 200-freestyle relay (1:41.76). Olson got the group out to a blazing start, as she swam the first leg in 23.80.
The Campbell sisters, Olson and Rachel Wong finished second in the 400-freestyle relay (3:42) behind a San Marino group's time of 3:36.22, which bested the previous league record Katy Campbell and Olson helped set in 2010 (3:40.18).
While Katy Campbell didn't outdo the 200- and 500-freestyle records she set last year (1:50.99 and 4:53.10, respectively), she still easily took first in both events with times of 1:51.57 and 4:55.86, respectively.
Samantha Campbell and Rachel Wong went on to take second in the 100 backstroke and 200-individual medley. Samantha Campbell finished second the 100 backstroke in 59.45, just behind San Marino's Tiffany Warmuth (58.56) and third in the 50 free (25.11). Wong took second in the 200 IM (2:21.16) and third in the 100 butterfly (1:04.55).
Three league records fell for La Cañada on the boys side, where the Spartans won nine of the 11 races, with Bo Mattix and Brandon Nguyen having their hands in two each.
Nguyen grabbed an individual record in the 200-individual medley when he touched the wall in 1:52.17, which bested the previous record of 1:52.49.
"I just wanted to do my race, but at the same time I was thinking about the record to have something to shoot for," said Nguyen, who was tailed by teammate and second-place finisher Garrett Chin (1:54.47). "When they called my name [before the race] I just thought, 'Let's do this.' I felt a shot of adrenaline go through my whole body."