- Up Flow Filter Up-flow filters are sometimes used for swimming pool water filtration, where the key advantages are high flow rate, reduced filter maintenance, and overall reduced filtration costs.
- Ultraviolet (UV) Sanitizer Ultraviolet (UV) sanitizers are installable systems designed to sanitize swimming pool water of harmful microbes without the use of chemicals.
- Ultraviolet (UV) Radiation Ultraviolet (UV) radiation describes specific ultraviolet rays of energy emitted from the sun, which swimmers and swimming pools and pool water are exposed to.
- Unstabilized Chlorine Unstabilized chlorine is a form of chlorine added to swimming pools for use as a sanitizer, but does not contain a stabilizing agent such as cyanuric acid, which increases the time chlorine can remain stable in swimming pool water.
- Unbalanced Water In important goal of owning a pool is to keep the pool water balanced, which can reduce maintenance costs, prevent eye and skin irritation of swimmers, and keep the water looking clean and clear.