This study provides detailed experimental insight into the biomineralization of tridacnid shells, which play an important role in tropical reef ecosystems. By growing calcifying organisms under tightly controlled aquarium conditions, the work reveals key mechanisms governing carbonate skeleton formation that are otherwise difficult to observe. These findings are relevant not only for understanding the biology of photosynthetic calcifiers, but also for paleoclimate and paleoenvironmental reconstructions that rely on biogenic carbonates as archives of past ocean conditions.