The Dons, ranked No. 4TK in the CIF Southern Section after knocking off Loyola at the Tournament of Champions, try to complete a perfect 8-0 run through the Channel League against San Marcos, which took a set off them earlier in the season. The Royals have to contend with Will Rottman, who had 27 kills against Loyola, and Matt Suh, a sophomore libero who parries numerous scoring opportunities. 6:30 pm. JR Richards Gym, S.B. High, 700 E. Anapamu Street. $3-$5. Call 966-9101 x5010.