EHEIM Undergravel filter throughflow principle
for planted aquaria
5.0 (2)The EHEIM undergravel filter forces a slight current of water to rise through the bottom gravel from below. As a result oxygen-requiring bacteria, which process all organic waste products to biologically harmless substances, settle there. The bottom gravel will no longer become clogged, and as well as acting as an extra biological filter, it aslo encourages rich plant growth.
