Bob Lowry on Dialing in Free Chlorine the Right Way
Your pool can look fine on paper and still be losing the chlorine battle. We dig into the frustrating “problem pool” scenario where you’re pouring in gallons of chlorine and the free chlorine (FC) reading barely budges, then break down what’s really happening when chlorine gets consumed faster than you can add it. With Bob Larry’s help, we walk through how to think like a detective: look at the environment, the deck, landscaping, runoff, bather load, and even the odd stuff people don’t mention like rinsing tools or chemicals in the pool.
From there, we get practical about chlorine demand, including the idea of negative chlorine demand where your first big doses are basically paying off a hidden deficit. We talk through a proven cleanup strategy: raise FC to a strong level and keep it there for 24 to 48 hours so the pool actually finishes oxidizing contaminants and knocking out algae, instead of slipping back into the same cycle. We also touch on an underrated cost saver for commercial pools and busy backyards: getting swimmers to rinse off first can dramatically reduce what chlorine has to burn through.
Finally, we tackle the classic complaint: “My chlorine is 3 to 5 ppm but algae keeps coming back.” The missing link is cyanuric acid (CYA) and how it changes chlorine effectiveness. We explain the 7.5% of CYA rule for setting a reliable free chlorine target that prevents algae, plus why consistency between service visits matters so much in warm, sunny conditions. If this helped, subscribe, share the episode with a pool owner or tech, and leave a review so more people can stop wasting chlorine and start keeping water clear.
We troubleshoot the pool that burns through chlorine and still reads near zero, using a detective mindset to track down hidden sources of chlorine demand. We also explain why “normal” free chlorine targets can still allow algae, then land on a practical CYA-based chlorine rule that keeps pools clear.
• identifying real-world chlorine killers like yard debris, runoff, deck wash water, and heavy bather load
• spotting sneaky contamination from cleaners, solvents, and tool rinsing
• understanding early algae growth, biofilm, and why algae is mature when you finally see it
• recognizing negative chlorine demand when big doses barely move the test result
• holding a high chlorine level for 24 to 48 hours to fully oxidize organics and kill algae
• reducing chlorine usage by having swimmers rinse off before getting in
• using the 7.5% of CYA free chlorine target to prevent algae
• keeping free chlorine consistent between service days to avoid fast blooms
Join the Pool Guy Coaching Program. Get expert advice, business tips, exclusive content, and get direct support from me. I'm a 35-year veteran in the industry. Whether you're starting out or scaling up, I've got the tools to help you succeed. Learn more at swimming poollearning.com.
If you're looking for other podcasts, just go to my website, swimming for learning.com.
If you're interested in the coaching program, you can learn more at pullguycoaching.com.
Support the Pool Guy Podcast Show Sponsors!
HASA
https://bit.ly/HASA
The Bottom Feeder. Save $100 with Code: DVB100
https://store.thebottomfeeder.com/
Try Skimmer FREE for 30 days:
https://getskimmer.com/poolguy
Get UPA Liability Insurance $64 a month! https://forms.gle/F9YoTWNQ8WnvT4QBA
Pool Guy Coaching: https://bit.ly/40wFE6y
Thanks for listening, and I hope you find the Podcast helpful! For other free resources to further help you:
Visit my Website: https://www.swimmingpoollearning.com
Watch on YouTube: https://www.youtube.com/@SPL
Podcast Site: https://the-pool-guy-podcast-show.onpodium.com/
UPA General Liability Insurance Application: https://forms.gle/F9YoTWNQ8WnvT4QBA
Pool Guy Coaching Group
Join an exclusive network of Pool Service Technicians to access the industry’s leading commercial general liability insurance program. Protect your business.
Premium is $64 per month per member (additional $40 for employees and ICs)
$59 per month for Pool Guy coaching Members - join here! https://www.patreon.com/poolguycoaching
Limits are $1,000,000 in occurrence and $2,000,000 in the aggregate - Per member limits
[ $1,000,000 per occurrence and $4,000,000 aggregate available for $75 per month ]
$50,000 in HazMat Coverage - clean up on-site or over-the-road
Acid Wash Coverage - Full Limits