The Helix Bio-Mechanical Waterfall Filter is a filter that uses
lava rocks and a large biological chamber for biological filtration,
nitrate reduction and water polishing. This
filter uses an air-assisted cleaning feature that makes it possible to
flush out the filter through high and low bottom drains. The high bottom
drain removes surface scum, while the low bottom drain removes heavy
solids. Made of a heavy-duty rotational molded HDPE construction. The
stainless steel hardware and high quality plumbing parts are made to
extend the filter's life. Includes air manifold for air-assisted cleaning and a 2" Bulkhead (Not pre-drilled, so that you can chose right or left side). Does not require a lid, so can be covered by a large stone or faux rock.