The spring of the 505m cave is part of the great Schällbach drainage system. It is only a small accessible part of it.

The Schällbach disappears approximately 600m to the south-west of the cave entrance into the Schällbach ponor – a small shaft cave (see board 7). It runs through part of this cave, drops into a siphon and surfaces here from beneath the Boulder-choked Spring (4 Siphon). After another 100m the stream disappears again (5 Siphon), and reappears farther down the valley as a tubed spring, emptying into the Ibach.

The Röhrenquelle (Tubed Spring) is no longer recognisable as such because it is hidden by the Ibach embankment. Of special interest is the fact that at high tide this cave acts as a relief channel for the tubed spring. The water level in the cave rises by about 20m before the whole passage is flooded. It then surfaces via the Boulder-choked Spring entrance and flows into the Ibach.

The cave is only accessible when the first two siphons have been pumped out, but some depressions remain full of water and require freediving or diving with adequate equipment.