Slug in DWC

[Dan Ponton]

I have an exterior DWC and I have a layer of brown/green slug on the bottom. Any Ideas what it is?

The leaves I clear out every so often.

[TCLynx]

Those are the find solids settling out of the system.  If they build up too much in DWC and manage to start coating the plant roots, it will stunt the plants.

Beware, when you do go to scoop them out  you will also stir them up quite a lot and may cause some spikes of things like nitrite in your system.  Those solids are why most DWC systems have settling tanks and net tanks and other types of filtration before the DWC so that the fine solids don't get into the DWC beds.

Those solids make wonderful worm food.