The run went quite smoothly except the beginning. I started the standard loop from the "Nachtigall" and began by ascending the Merkur mountain. I started before sunrise, at 6:45 am. It was quite foggy and even though I used a head-lamp I got lost twice. We had heavy snowfall the past couple of weeks but, with very few exceptions, it had all melted away on the trail. There was a little bit of rain and the temperature was 3° Celsius. I had packed a banana, 5 energy bars and 4*0,5l soft flasks (two with water/two with electroyltes). I only used the banana, 3 bars, 1 water, and 2 electrolytes. In order to have a chance at the unsupported FKT I did not take any breaks but I did speed-walk up the notoriously steep section up from Lautenbach towards the Lautenfelsen. I didn't taper for this FKT so with more rest and slightly better weather I think it is very doable to break 5 hours for the next unsupported FKT attempt.
Splits:
Nachtigall: 0km, 0hr0min
Gernsbach train station: 12 km, 1hr25min
Loffenau: 17 km, 1hrs56min
Lautenfelsen: 23 km, 2hrs44min
Murg: 33,5 km, 3hrs:55min
Nachtigal: 44,1 km, 5hrs17min