Na+ 20 to 140: K+ 2 to 50 mM
||Haoxing Xu and Dejian Ren, Lysosomal Physiology, Annu. Rev. Physiol. 2015. 77: 57–80 doi: 10.1146/annurev-physiol-021014-071649 p.59 3rd paragraph
|| Steinberg BE et al., A cation counterflux supports lysosomal acidification. J Cell Biol. 2010 Jun 28189(7):1171-86. doi: 10.1083/jcb.200911083  Wang X et al., TPC proteins are phosphoinositide- activated sodium-selective ion channels in endosomes and lysosomes. Cell. 2012 Oct 12 151(2):372-83. doi: 10.1016/j.cell.2012.08.036PubMed ID20566682, 23063126
||Primary source  abstract: "To assess the individual contribution of counter-ions to acidification, [investigators] devised means of reversibly and separately permeabilizing the plasma and lysosomal membranes to dialyze the cytosol and lysosome lumen in intact cells, while ratiometrically monitoring lysosomal pH."
||P.59 3rd paragraph: "The luminal Na+ and K+ concentrations have been estimated in only a few cell types. The values range from 20 to 140 mM for Na+ (higher than [Na+]cytosol of ∼12 mM) and from 2 to 50 mM for K+ (lower than [K+]cytosol of ∼150 mM) (primary sources)."