SolveSAPHE (Solver Suite for Alkalinity-PH Equations) provides a collection of Fortran 90 routines to solve the total alkalinity–pH equation, which relates total alkalinity and pH for a given set of total concentrations of the acid–base systems that contribute to total alkalinity in a given water sample. This version (1.0.1) of SolveSAPHE was first published as a supplement to the paper: Guy Munhoven (2013) Mathematics of the total alkalinity-pH equation – pathway to robust and universal solution algorithms:the SolveSAPHE package v1.0.1. Geosci. Model Dev., 6, 1367–1388, 2013 (URL: https://www.geosci-model-dev.net/6/1367/2013 or doi:10.5194/gmd-6-1367-2013) The package provides six different solvers for the alkalinity-pH equation: two of the six solvers implement variants of a newly developed iterative algorithm, designed to assure convergence with any physically meaningful chemical composition; the four others are re-implementations of previously published algorithms. Furthermore, a collection of parametrizations for stoichiometric constants for seawater samples is included.

Financial support for the development of SolveSAPHE was provided by the Belgian Fund for Scientific Research – FNRS (FRFC grant 2.4571.10). Guy Munhoven is a Research Associate with the Belgian Fund for Scientific Research – FNRS.