The difference between this and a pond is that your nutrient concentrations will be 100x what they are in a pond (where oxygen is the limiting factor). That will make for a lot more biological life (like algae) than you'd see in a pond. Given that, I'd say that blocking all sunlight is pretty much required. You also might want to take a bath after, and avoid opening your eyes.
Per the NYT, the bacteria is
good for you. There are other organisms and materials in there that might not be so good.
