Supplement Feature - February 2021
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Just Keep Swimming

The 2021 Aquatic Trends Report

By Emily Tipping


Water & Resource Management

Respondents to the Aquatic Report survey indicated the various types of systems used to filter their water and maintain water quality, as well as their use of secondary disinfection and their methods for conserving resources, such as water, chemicals and energy.

When it comes to pool filtration, sand filters are still dominant, though the number of respondents using them has fallen over the past three years, from 72.2% in 2018 to 66.2% in 2020. Diatomaceous earth (D.E.) filters also saw a decline in use in 2020, from 20.1% in 2019 to 16% in 2020. Regenerative media filters (RMFs) have seen fairly steady use over the past three years, with around one out of 10 respondents (9.2%) using them in 2020. (See Figure 12.)

A majority of respondents—80%--said they currently use chlorination systems at their aquatic facilities, while 11.6% are using bromination systems. More than one-third (35.6%) said they currently use a tablet chlorination system, while 7% are using salt chlorine generators.

Looking forward, 11.6% of respondents said they had plans to add new systems or update existing systems at their aquatic facilities over the next three years. As that relates to pool filtration, respondents were most likely to be planning to add either RMFs or sand filters. Some 16% planned to add RMFs, and 16% planned to add sand filters. Another 13.3% are planning to add D.E. filters at their aquatic facilities.

For the most part, the numbers of respondents planning these system changes at their facilities have all decreased from last year. The one exception is salt chlorine generation. Some 12% of respondents said they are planning to add salt chlorine generators, up from 10.5% in 2019.

When it comes to secondary disinfection, which is recommended by the Model Aquatic Health Code (MAHC) as a way to improve water quality and prevent recreational water illnesses, 35.8% of respondents indicated that they currently employ some form of secondary disinfection, down from 36.4% in 2019, but still above 2018's 32%. More than three-quarters (78.8%) of respondents using secondary disinfection said they are using UV systems, down from 84.7% in 2019. Another 10.8% are using ozone systems (up from 6.5%), and 4.1% are using AOP (advanced oxidation process) systems, up from 4%. Some 6.3% said they are using some other form of secondary disinfection. (See Figure 13.)