Catalyzes the dephosphorylation of 2-phosphoglycolate. Also has significant, but less efficient, pyrophosphatase activity, since it is able to catalyze the release of phosphate from inorganic pyrophosphate (PPi). 2-phosphoglycolate + H2O = glycolate + phosphate Binds 5 Mg(2+) ions per homodimer. Inhibited by Ca(2+) ions and by high chloride ion concentration. By contrast, low chloride concentration (up to 50 mM) slightly activate the enzyme. Homodimer. Belongs to the HAD-like hydrolase superfamily. Archaeal SPP-like hydrolase family.