Sludge is removed from the basin via the skim channel. This is realized by means of a slotted skimming tube and a floating sludge pump that is arranged in a discharge box. The skimming tube has retainers that can be adjusted with spindles and handwheel to adapt the channel to the optimum water level. In addition to that, the skimming tube can also be delivered with a fully automated version which automatically adapts to the water level.

Rehart produces skim channels with and without paddle system. Both types are identical, except that the skim channel with paddle system cannot be lifted.

Lengths are arbitrary, the standard size is DN250.