For those curious:

”It’s the extremely high level of salinity that gives the lagoon its unusual hue, and its vibrancy changes with the seasons and time of day. The best time to visit is on a clear day, around mid-morning or sunset. There are a number of places to stop and view this natural phenomenon along Port Gregory Road.”

Source: https://www.westernaustralia.com/en/attraction/hutt-lagoon/59cb40e112f8967834c0e22f