  This study reports the performance and light yield of 1% concentration
water-based liquid scintillator (WbLS) deployed in a 1000-liter detector. A
light yield of 99$\pm$15 photons per MeV is determined by comparing data with
simulation. This result aligns with our previous light yield determination
using smaller detectors, thus establishing a solid foundation for the ongoing
development and deployment of WbLS in larger-scale detectors. The feasibility
of in situ preparation and the stability of light yield in WbLS are
demonstrated, reinforcing its suitability for long-term experimental endeavors.
