Involved in the hydrolysis of the beta-gamma-phosphoanhydride linkage of triphosphate-containing substrates (inorganic or nucleoside-linked). Catalyzes the hydrolysis of inorganic triphosphate (PPPi), which could be cytotoxic because of its high affinity for calcium ion, thereby interfering with calcium signaling. It also hydrolyzes slowly thiamine triphosphate (ThTP). YgiF is a specific PPPase, but it contributes only marginally to the total PPPase activity in E.coli, where the main enzyme responsible for hydrolysis of PPPi is inorganic pyrophosphatase (PPase). H2O + triphosphate = diphosphate + phosphate Inhibited by calcium ion and activated by magnesium ion. Optimum pH is 8.5. Cells lacking this gene do not show decrease of specific PPPase activity.