Because the Südbad is closed until the 3 August I went into the Nordbad and I have to say I liked the sauna environment there a lot.
The price after 20:00 is exactly the same like in the Südbad however Nordbad has more saunas and it has an open air sauna and a cold water bath.
There is also a cold and warm water baths inside and several inside saunas and a steam bath.
As one of couchsurfing.org members wrote in the forum post – http://www.couchsurfing.org/group_read.html?gid=1223&post=9627911 it’s quite a good place for spending healthy quality time and for having some interesting and fruitful conversations.
There is also a “quiet room” if you aren’t up to a good conversation and need your peace and quiet.