A gravity filter often refers to an entire gravity filtration system, where swimming pool water is fed to the top of a container, and trickles down through a filter medium by the force of gravity.
What is a swimming pool Gravity Filter?
A gravity filter, or gravity filtration system, is one of two main filtering concepts, with the other being vacuum filtering. A gravity filter operates by pumping water to the top of a container filled with a filter medium, which the water then flows onto the medium and falls through by gravity. As the water travels through the media, particulates are caught and filtered water flows out through the bottom of the filter container.
There are numerous types of gravity filter systems, with examples including shallow bed, deep bed, travelling bridge, packed filters, among others. The filtration media can also vary, with sand, activated carbon, diatomic earth (DE), and gravel or aggregate being common substances used. The size of the particles to be removed from the water determines which filter media to use. The effectiveness of a gravity filter to catch and remove particulate from water can be enhanced by the use of a flocculant, which binds particles together, forming larger structures that are caught in the filter medium that otherwise pass through the filter.
Gravity filters are commonly used for swimming pools, as gravity filters and filter media are inexpensive to purchase and maintain, they are reliable, and filter out most particulate found in swimming pool water. The size of the pool and the bather load should be factored in when determining what size of gravity filter to install.