Enzymes and phosphate reducing products have been used in the pool and spa industry for many years. Claims about their effectiveness have taken on a life of their own. Although the products can be extremely useful for pool owners and maintainers, they have limitations. This article explains what these products are, what they are capable of and what they cannot do. Information on how best to use them to help pool operators will also be covered.
Phosphate reducers are specialty chemicals used to remove phosphates from pool water. They are usually aluminum or lanthanum salts which, when added to water, produce insoluble phosphate compounds which are removed by filtration, suction or both.
It should be noted that not all phosphates found in swimming pools are bad. Certain phosphates (polyphosphates) and other compounds containing phosphorus are excellent sequestering agents, protecting the pool from metal stains and scale. Certain phosphates (namely orthophosphates) are known to be a food source for algae. Phosphate reducers were introduced as a way to limit this food source; thus limiting the ability of algae to grow in the pool. However, since these products are not registered with the EPA as algaecides, their labels cannot claim algae control. Nevertheless, many believe that these products will kill the algae.
Myths about phosphates
The removal of phosphates reduces or eliminates the need to maintain an appropriate disinfectant residual. It is simply not true. An appropriate sanitizer residual must be maintained in the pool at all times and in all areas of the pool to ensure proper disinfection. As an added benefit, maintaining this residual and shock treatment regularly will also prevent algae from becoming a problem, regardless of the existing phosphate level.
The elimination of phosphates eliminates the need to use an algaecide. Since removing phosphates from pool water does not kill algae, an algaecide is always recommended. Maintaining your residual sanitizer and using an algaecide regularly will prevent any unexpected algae blooms.
Removing phosphates will kill algae. If this were true, then products could make algaecide claims on their label. Algae can store phosphates in their cells, allowing them to survive for periods of time in the absence of phosphates. As some of these cells die, their phosphates can be used by the surviving algae as a source of nutrients.
Phosphates create a chlorine demand in pool water. It’s wrong. The phosphates are already at their ideal oxidation level, so the chlorine does not react with them. For this reason, phosphates do not create a chlorine demand. The two are simply not related.
Once phosphates are removed from a swimming pool, they will not come back. Phosphates are common in the environment and are constantly introduced into the pool from a variety of sources including swimmers, leaves, insects and other water treatment products. In fact, phosphonate-based sequestering agents are some of the best products available to provide protection against metal stains and scale. These phosphates are not orthophosphates and are not useful to algae as a food source. It should be noted that the orthophosphates themselves are not useful as sequestrants.
Despite the limitations, phosphate reducers can still be an effective tool for managing swimming pools if used as part of a routine maintenance program. Since phosphates are so common in the pool, phosphate levels need to be diligently monitored to ensure they stay low. This will ensure that any issues that arise can be minimized. Additionally, when choosing a sequestering agent, the pool operator will need to decide if the benefits of using a phosphate reducer outweigh the benefits of using a phosphate-based sequestering agent. phosphorus to prevent metal stains and scale (usually polyphosphates are used, not orthophosphates which feed algae).
Enzymes are specialty chemicals that are used to help eliminate or reduce the severity of water line scum lines or their severity, improve sanitizer efficiency by reducing organic load, and reduce filter cleaning. Enzymes are proteins produced by biological processes that act as catalysts to speed up reactions by lowering the level of energy required for that reaction to occur. Enzymes are selective in nature, with specific enzymes working with different types of products. For example, an enzyme that will catalyze the breakdown of an oil molecule will probably have little effect on a protein or a starch.
The use of enzymes in the pool has several effects. For starters, by breaking down the oils and other complex molecules found in swimming pools, the amount of material available to form scum lines at the water’s edge can be greatly reduced. Also, because enzymes help break down some very complex molecules in water, oxidizing disinfectants such as chlorine and bromine are more effective at breaking down these contaminants and then become more available for their intended use in killing bacteria. Another benefit is that by breaking down these large, complex products, the filters will be less likely to clog, resulting in longer cycles between cleanings. Since chlorine will destroy enzyme activity over time, their activity time in the pool is limited. For this reason, they should be used as part of a regular maintenance program to maintain benefits.
Enzymes are living organisms. It’s not true. Enzymes are produced by living beings but they themselves are not alive. This means they cannot be killed. Instead, their ability to help catalyze reactions can be destroyed (by high heat, chemical incompatibilities, etc.).
Synthetic enzymes. There is some confusion in the industry with terms like synthetic versus natural enzymes. Enzymes, by their very nature, are produced by natural things and are therefore themselves natural. Synthetic enzymes are substances that are not enzymes but mimic their activity. Since they are not actually enzymes, they cannot be labeled as such and none are known to be used in the pool and spa industry.
All enzymes look alike. Broad-spectrum enzymes are products that contain a wide range of enzymes and enzyme activities. Other products contain selected or targeted enzymes, which means the proteins are selected to target particular types of contaminants that need to be broken down. Products containing selected enzymes may also be broad-spectrum in that they are mixtures of selected enzymes and broad-spectrum enzyme products may not necessarily target the desired contaminants. For this reason, it is important to know what type of enzyme product you are using to achieve the desired result.
The enzymes will break down any contaminants. Enzymes will not destroy all contaminants in the water. Enzymes will only act on substances to which they can bind and therefore only certain contaminants will act, depending on the types of enzymes present.
Enzymes and phosphate reducers are specialty products that can be used to help maintain water clarity and pool aesthetics. Although each type of product has advantages and limitations, if the right products are chosen and used as part of a regular maintenance program, they can be effective tools in managing a pool or spa.
Weber is responsible for quality and technical services at Arch Chemicals, now part of Lonza. A 16-year industry veteran, he is also a consultant for the APSP Recreational Water Quality Committee.
Enzymes are proteins that act as catalysts, speeding up chemical reactions. The substance on which the enzyme reacts is called a substrate, which fits perfectly into an enzyme. The enzyme weakens the bond in the substrate, facilitating the reaction.