Zheng Wen clocked 55.86s in the men's 100m backstroke super final, while in the men's 200m breaststroke super final, Christopher Cheong came from behind to beat Lionel Khoo and set a new national mark of 2 minutes 16.70 seconds.
The Nanyang Primary student, who turns 11 on August 13, took part in nine events.
Zachary's achievements also saw him win the Most Valuable Swimmer award for boys on points.
Six girls set seven new age-group records on Day 2 of the championships.
This added to the two records he set the day before in the 200m breaststroke and 400m individual medley.
Claresa Liau and Charity Lien set two meet records each, while 8-year-old Lynette Some was the youngest record breaker of the day.
Zachary, who turns 12 on June 14, broke the 200m breaststroke and 400m individual medley meet records by 13 and 26 seconds respectively.
Singapore won four gold, six silver and 15 bronze medals at the 17th edition of the Games.
