Floating pool skimmer includes a hollow unit above the water surface and a filter chamber between a water intake and a water outlet. The water moves through the skimmer as it moves about on the water surface. This device has the disadvantage that it requires propulsion on the surface of the water. It collects the leaves and debris on the surface. The debris is directed downwards by water jets into a mesh bag. The device relies on the use of these water jets to clean the pool and for propulsion, which requires extra piping and pumps.

Flocculants, or flocculating agents, are chemicals that are used to promote flocculation by causing colloids and other suspended particles in liquids to aggregate, forming a floc. Flocculants are used in water treatment processes to improve the sedimentation or filterability of small particles. For example, flocculants may be used in swimming pool or drinking water filtration to aid removal of microscopic particles, which would otherwise cause the water to be cloudy, and which would be difficult or impossible to remove by filtration alone. Many flocculants are multivalent cations such as aluminum, iron, calcium or magnesium. These positively charged molecules interact with negatively charged particles and molecules to reduce the barriers to aggregation. In addition, many of these chemicals, under appropriate pH and other conditions, react with water to form insoluble hydroxides which, upon precipitating, link together to form long chains or meshes, physically trapping small particles into the larger floc. Long-chain polymer flocculants, such as modified polyacrylamides, are manufactured and sold by the flocculants producing business.

Gravity Filters consist of an open-topped box, drained at the bottom and partly filled with a filtering medium, usually clean sand. Gravity filters are usually employed for municipal applications and on some industrial applications. Gravity filters are open to the atmosphere at the top and the water percolates through the filter bed by gravity. Gravity filters are free surface filters that are much more commonly used for municipal applications. Gravity filters are usually made of concrete and are operated similarly to sand filters.