A dialysis machine 120 comprises a reservoir 130 having both liquid and gas inlets 131, 141 and outlets 133, 143, and wherein the reservoir 130 is provided as a part of both liquid and gas circuits. The gas circuit further comprises an air pump 160 and an air heater 134 and is arranged such that, in use, gas flowing in the gas circuit permeates liquid in the reservoir 130 so as to control and regulate the temperature of the liquid. The liquid may thus be used in the preparation of dialysate and/or heat sanitization of the dialysis machine 120. A semi permeable membrane, preferably a mesh 144, may also be arranged in the reservoir 130 such that as air rises up through the water held in the heating and de-aeration chamber 130 micro bubbles are formed at the mesh 144 the micro bubbles serving simultaneously to heat the water and draw out of solution other gasses dissolved in the water. A float valve 146 may also be provided in the reservoir 130.
