Another tank feature... Flushing System... the return pump (T-off) will send jets of water through the PVC structure drilled with holes at strategic locations. The entire structure will be covered with rock scape... flushing the LR and shell bed from top, bottom, left, right... almost all directions. Pushing detritus and wastes to the front to be carried to the overflow by my Tunzes
The pix shows only part of the system