ALC stands for Adventure Lab Cache. This mystery cache is a bonus cache for ALC "Xikou 錫口". To get the passcode for this cache, you have to complete the ALC (5 locations, non-sequential) and find important information in the journal. Use Certitude to verify your passcode and obtain final coordinates.
Download the Adventure Lab App and click the link Xikou 錫口. Follow the Adventure Lab to visit some interesting locations around Xikou.
BYOP, Enjoy!
You can validate your puzzle solution with certitude.
Thank alankunHK, B.T, Haima, Incredible_Kidd, IzuShoto, josephshih13, ktujon, moooment, NoMembers, Norpero, penetrate, seanliu1, stacyhsu, y2konion, littlepuputing for the FP given.