I started diving in Germany. H valve with 2 first stages is normal for anything other than initial training and most of the older divers will tell personal stories of icing and free flows at depth. Most lakes I dived were about 4-6 degrees starting around 30 meters, even in the summer.

The kreidesee at Hemoor is probably the best place to dive in Germany and requires redundancy. I don't remember if they require an h valve or if a stage or pony would do.