Some halophiles are colourful microbes like purple sulphur microorganisms, the reddy/orange Salinibacter ruber and pink-coloured algae known as Dunaliella salina. The combo of such microbes, And maybe some Other people, describes the pink colour on the lake. (Should the science behind the pink water at pink Lake Hillier interests you, https://edwinp395mnn1.wikidirective.com/user