The lagoon itself is a man-made construction, its bottom is covered by sand and gravel. The characteristics of the water are unique in many ways. It contains a large amount of minerals, is alkaline and well suited for bathing. Due to its chemical composition, undesired bacteria and vegetation do not thrive in the lagoon making chloride or any other disinfectant redundant.
Geothermal water in Iceland usually contains some sulfur. In this area the strength of the chemical is greater than others. Therefore is should be avoided to take jewelry from brass or silver into the water, they become black and can be damaged. Sulphur, however, is considered to have a positive effect on asthma and other respiratory diseases, and many of the trace elements in the water are considered to have a good effect on the development of skin problems.