We report our experiences implementing standards-based grading at scale in an Algorithms course, which serves as the terminal required CS Theory course in our department's undergraduate curriculum. The course had 200-400 students, taught by two instructors, eight graduate teaching assistants, and supported by two additional graders and several undergraduate course assistants. We highlight the role of standards-based grading in supporting our students during the COVID-19 pandemic. We conclude by detailing the successes and adjustments we would make to the course structure. * We thank our course staff for their hard work and support, which was instrumental in implementing SBG. We thank S. Krinsky for personal communication sharing her course structure and advice during our initial planning. We thank V. Dunn for compiling detailed grade data dating back several years. JAG thanks C. Heckmann, B. Hayes, D. Larremore, B. Waggoner, and A. Clauset for useful feedback on part of a draft. ML wishes to thank B.H. Payne for useful feedback on part of a draft, A. Book and A. Edwards for helpful discussions regarding the changes made in Summer '21, as well as A. Book for helpful feedback on the development of a course text [Lev21]. We thank the anonymous referees for their helpful feedback. JAG was partially supported during this work by NSF CAREER award CCF-2047756.