If you have time you should definitely take a tour to El Tatio. All tour providers offer it, but it can also be easily done with a rental car. We were only there around midday, all the tour buses had left and we were able to enjoy the area in peace.
From the viewpoint you have a beautiful view of the geyser field. It is the largest geyser field in the southern hemisphere and the third largest in the world with 110 erupting springs. de.wikipedia.org/wiki/El_Tatio
Allegedly, the visit of the Geyser field at the time of sunrise is the most spectacular. We started well 1 1/2 hours before sunrise in San Pedro de Atacama with our own rental car. You do not have to worry about driving in the dark, the road is already very busy at this time. On the way back you can marvel at the many beautiful hotspots along the way.