Do not expect a crystal-clear, blue surface. The lake water is unique in its reddish colour, which is caused by iron compounds. Already in the Middle Ages, slate was mined here and in the 18th century the locals extracted sulphuric acid from it in a specific way. After the end of mining, the pit formed a lake up to 60 metres deep, which is not really suitable for swimming. On the contrary, it is a weak solution of sulphuric acid, so it is a completely sterile environment without any sign of life. Even in spite of this, Hromnice Lake is definitely worth a trip.
If you come by car, park directly in the village of Hromnice. Then follow the gently rising path up the hill, past the monument to The Three Saints. After about a hundred metres you will find yourself at the first lookout point over the lake, which you can walk all the way around.