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Back to basics: Choosing the right clarifier

Multi-functional products

There are many products that fall under a ‘multi-functional’ category such as oxidizing agents, dual-action phosphate, or contaminant removers. Most pool water clarifier options are liquid, but contaminant removal technologies are also available in solid forms. Some of the liquid clarifiers might be highly concentrated and require pre-dilution, others can just be broadcast over the water surface, while others may recommend superchlorination. Often, chlorinating shock products may even contain built-in clarifiers to aid in filtration. Many service technicians even use water clarifiers as a part of their weekly maintenance. It is usually more cost-efficient to prevent problems rather than resolve them.

Phosphate levels increase over time, especially when it is present in the source water or after adding certain chelating/sequestering products. Other ways it can enter is through fertilizers, skin, dead bacteria, or even bather waste. In saltwater pools, cloudy water can form in scale-inducing environments where the saturation index is too high due to hard water, high pH, and high total alkalinity. While some believe orthophosphate is the cause of cloudy water, it is generally not the case. When orthophosphate is high in concentration, it can bind with calcium and create problem-causing calcium phosphate scale. While cloudy water is an unfortunate side effect, greater problems can present themselves. For example, scale formation on an electrolytic cell can be quite damaging. Phosphate remover can react very quickly in the water as the lanthanum reacts with calcium carbonate and calcium phosphate, forming an insoluble compound that can either be removed by the filter or vacuuming. Phosphate removers are also filtration aids and may contain additional components used to either enhance filtration from either a polymeric or polyaluminum clarifier, surfactants, and often enzymes to break down body oils. Most phosphate removers contain a lanthanum compound—either lanthanum chloride or lanthanum sulfate. As some of the phosphate is being removed via the filter, the clarifying agents in these multi-action products continuously aid other contaminants or tiny particles as well.

Pool type/structure

Water clarity can even vary based on a pool’s design. Further, the number of returns, skimmers, and even the size of the filter in relation to the volume of water in the pool can be impactful. Above-ground pools come in many different variations, sizes, and shapes. Some types, for instance, will often use a one-size-fits-all pump and cartridge filter combination, one return, and sometimes, not even a skimmer. When pools are not equipped with skimmers, keeping the water clear will be quite difficult.

For some service techs, picking the right treatment for a cloudy pool can be overwhelming. However, when one is able to pinpoint the cause and take some of the pool’s other ‘quirks’ into consideration, deciding on the appropriate treatment can be a breeze.

Emily Johnson, born and raised in South Carolina, graduated with a degree in biological sciences and chemistry minor from the University of South Carolina in 2013. She is a recreational water enthusiast living in Atlanta with her two rescue dogs. Johnson has been working in research and development at BioLab Inc., a KIK Custom Products Company, since 2014. She can be reached via email at

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