A surface skimmer ( JBL TopClean II ) is a really useful addition to any external filter, as it keeps the water surface clean and ensures the water above the surface is ideally enriched with oxygen.
Normally the external filter sucks in the “dirty” water through the suction pipe whose intake strainer is situated just above the substrate. But this also means that the surface water is not drawn into the filter circulation. This often results in plant remains floating around and the possible formation of a so-called “surface scum”. The scum is a whitish “skin” formation on the water surface, comprised of bacteria and fungi, which prevents exchange of gases at the water surface.
With the JBL TopClean II you can now both suck off the surface water while still sucking in deep water. Due to an adjustment spindle which is easily accessible from above, you are free to choose the suction ratio of surface water to deep water and can adjust it indefinitely.
Another advantage is the floating top part which adapts to a changing water level (caused for instance by evaporating water).
The installation of the JBL TopClean II couldn’t be easier: Attach the semi-circular suction chamber to a rear corner of your aquarium and connect the suction pipe of the JBL TopClean II instead of the previous suction pipe to the suction hose of the external filter. Possibly needs to be re-started (priming). Once the water is flowing you can select the surface water /deep water suction ratio, using the adjustment spindle. You can see a red internal part through the lower suction slits. The higher this part is set, the more water is sucked in from the surface.
1. SURFACE WATER SUCTION : This is where the surface water is sucked down from the water surface.
2. ADJUSTMENT SPINDLE: This is where you can freely choose the surface water/deep water suction ratio.
3. DEEP WATER SUCTION: This is where the dirty water from the aquarium reaches the filter.
4. FLOATING SUCTION COMB: Adapts to the changing water level (caused for instance by evaporating water).