(Google translate) The water from the spring of Niška Banja stands out as a mixture of warm and cold components, the condition of which depends on its yield and temperature. Medicinal mineral water in Niška Banja is used from three sources of different temperatures and radioactivity.
At the corner of 248.47 on a wall about 2.5 meters below the surface of the terrain, there is the Main Springs, the main spa facility with the original Roman castle, made in the form of a dome well built in brick and brick layers, from which a warm water rises from the bottom and rises Under the top of the dome. The main springs are one of the most reliable homeothermic Serbian spa springs, with a minimum water flow rate of 35 l / sec and a water temperature of 38.2 ° to 38.5 ° S. The content of minerals in the water is insignificant. The dry residue is 0.286 g / l at 37.3 ° C. Water from the Main Spring belongs to radioactive homeotherms, whose radioactivity amounts to 10.53 to 13.4 Mahov units. The medicinal properties of the water of this terem was derived from radon and microelements.
The main springs supply water: Old bath (swimming pool number 3) dating from the seventeenth century and Master bath (swimming pools number 1 and 2) built in 1932.