This study investigates whether shortening the light/dark cycle affects the acid fluctuation and stomatal behavior of CAM (Crassulacean Acid Metabolism) plants, and how it influences their growth. Three common obligate CAM plants— Kalanchoe sp., Phalaenopsis spp., and cactus(cv. Momotaro)—were selected for the experiments. The plants were cultivated in custom-designed growth chambers, each equipped with an Arduino-controlled system that regulated the light/dark cycle via timers programmed with custom code and maintained temperature using fans. The plants were then subjected to four light/dark cycle treatments: 3L:3D, 6L:6D, 3L:9D, and 12L:12D (L = hours of light; D = hours of darkness). The results indicated that titratable acid concentration and stomatal opening varied with the light/dark cycle. However, the optimal cycle for growth differed among species, suggesting species-specific sensitivity to shortened light/dark cycles. For example, Phalaenopsis exhibited faster growth under the 6L:6D cycle than under the natural 12L:12D cycle. Under the 3L:9D cycle, Phalaenopsis received only half the total daily light energy compared with the other treatments, yet its leaf elongation exceeded half of theirs, suggesting a phenomenon that warrants further investigation.