According to an article on Healthy Water from the CDC, they make a bold statement that “The CDC recommends not using cyanuric acid or chlorine products with cyanuric acid in hot tubs/spas.”
Dichlor is a stabilized chlorine commonly used in hot tubs. The problem is hot tubs don’t need to be stabilized. They are not out in the direct sun all day like pools so they don’t need the UV protection that the cyanuric acid in dichlor offers.
According to J.R. Anderson in his article “A Study of the Influence of Cyanuric Acid on the Bactericidal Effectiveness of Chlorine” it takes 4 times as long to kill common hot tub bacteria when CYA is at 50 ppm and 6 times longer when CYA is 100 ppm.
There is a reason consumers rave about FROG @ease. They talk about less odors, the soft feel, and crystal clear look but mostly they talk about how easy it is to manage their water. When switching from dichlor, they realized a big difference! Here is what a few of them told us.
Centers for Disease Control and Prevention (CDC)
https://www.cdc.gov/healthywater/swimming/residential/disinfection-testing.html
CYA: Ally For Pools – Havoc for Hot Tubs
https://www.kingtechnology.com/images/AQ11-SC.pdf
Taylor Technologies stating “Both dichlor and trichlor are over 50% CYA by weight”
https://www.taylortechnologies.com/en/page/171/why-monitor-cyanuric-acid
National Center for Biotechnology Information Support Center (NCBI)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1256554/pdf/amjphnation00162-0123.pdf
Pool and Spa News about CYA
https://www.poolspanews.com/how-to/maintenance/what-to-know-about-cyanuric-acid_o
Pennsylvania Department of Health
https://www.health.pa.gov/topics/Documents/Programs/Operations-SOPRecommendations.pdf
Scientific papers
http://www.poolhelp.com/wp-content/uploads/2017/05/JSPSI_V2N1_pp34-41.pdf
https://pdfs.semanticscholar.org/45df/ab9228ad91446771722ca6a850eb8696f928.pdf
https://pdfs.semanticscholar.org/ba9b/4a37526b0a50b10586efef263ee144b3a143.pdf