Rounded diabase stones, should be placed on top of the heater or wood burning stove and cover around 1/3 of space. Other space of 2/3 in the bottom and in the middle part of the heater, should be covered with average, standard sauna stones. When the water seeps between the stones and drains to the bottom of underlying stones it forms a soft and pleasurably steam. The top surface of the heater or wood burner, should be covered with diabase stones. The steam will come from every stone, turning into a light, ethereal cloud of steam. In total, you will need to put around 20 kg of stones to cover the top surface of the heater and prevent water from fast leaking between the stones.