The figure is a notable exception to the usual limit of around 5,000 spectators permitted by Egyptian authorities for club games in the domestic league.
On Sunday, the authorities allowed 30,000 fans to attend Ahly's game in the African Champions League at Cairo International Stadium.
Arta Solar dealt a surprising blow to Zamalek with a 2-0 victory in the first leg of the CAF Confederation Cup round of 32 last week.
This game was played at Azam Complex Stadium in Tanzania due to CAF's decision not to register Arta Solar Stadium in Djibouti.
Zamalek, who clinched the Confederation Cup title in 2019, will receive a boost with the return of key player Ahmed 'Zizo' Sayed, who has now recovered from injury.
The second leg poses a challenging task for Zamalek as they strive to secure a spot in the round of 16.
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