One popular region to do diving is the Salzkammergut in Austria. Numerous large and small lakes in an alpine setting. Conditions are the same as for the Bodensee: deep, dark, cold, clear.
The viz can be 100’/30M which is as good (if not better) than the Red Sea. Of course the marine life and color is not quite like the Red Sea!
Facts about Freshwater lakes, Grundsee
It is in Austria- The typical depth is 0-20 Metres 0-60 Feet.
- The typical visibility is 10-30 Metres 30-100 Feet.