Two complementary executable water-quality modeling tools (CausticTitration_PO4mg.exe, CausticTitration_PO4moles.exe) simulate equilibrium processes that may attenuate dissolved concentrations of phosphate (PO4) plus associated concentrations of iron (Fe), aluminum (Al), manganese (Mn), calcium (Ca), and sulfate (SO4) as pH and other solution characteristics change during titration with a caustic