The ista Multi-Surface Skimmer prevents dust and protein layer formation on the aquarium water surface. Pollutants on the water surface can filter the light that reaches the plant. The ista Multi-Surface Skimmer helps maintain a crystal clear water surface, allowing for effective gas exchange and proper light for plants. With a self-floating water inlet chamber, it automatically adjusts itself with the change of water level. It's designed to work with a hang-on filter or small canister filter. The Multi-Surface Skimmer connects to the inlet of the filter. Compatible with hose or filter inlets from 1/2" to 5/6" outside diameter.