“99% trichlor” sounds like a mic-drop statistic, but it’s also one of the most persistent sources of confusion in pool care. We sit down with Bob Lowry to untangle what that number actually means, why “purity” is not the same thing as “chlorine strength,” and how the industry’s use of available chlorine (based on a chlorine gas reference) warps the way products get talked about on the truck and at the counter.

We walk through the real chemistry behind the label: what free chlorine is doing in the water, why the comparison standard matters, and how trichlor’s makeup includes cyanuric acid that builds over time. If you’ve ever heard someone say liquid chlorine is “weaker” or tablets are “the strongest,” this conversation gives you the language and logic to explain the difference clearly to clients and techs without hand-waving.

Then we pivot to cal-hypo, especially the idea that it “doesn’t add much calcium.” Bob breaks it down in practical terms you can use in the field: if you add cal-hypo to raise free chlorine, you are also raising calcium hardness in a predictable way, and that matters a lot in hard-water regions. We also compare how different percentages of available chlorine change dosing, why some cal-hypo tablets can require much more product than trichlor, and how to think about true cost per usable chlorine. You’ll also hear where to find Bob’s resources (pci.org and pccti.online) and how we can help you level up your pool service business.

Subscribe for more pool chemistry myth-busting, share this with a tech who still quotes the “99%” line, and leave a review with the biggest pool maintenance myth you want us to tackle next.

We revisit a classic pool chemistry myth with Bob Lowry and unpack why “99% trichlor” does not mean you are getting 99% chlorine in your pool water. We also run the numbers on cal-hypo side effects so you can predict calcium hardness rise over time instead of getting surprised by scaling later.  
• why “99%” on trichlor labels refers to purity, not chlorine content  
• how “available chlorine” is a comparison standard tied to chlorine gas  
• what actually gets added when you use trichlor, including cyanuric acid  
• why cal-hypo steadily raises calcium hardness and how to estimate it with ppm math  
• how different cal-hypo strengths and tablet percentages change dosing and cost  
• a simple spreadsheet method to compare true cost per equivalent chlorine  
• where to find Bob Lowry’s resources and tech bulletins online  

Are you a pool service pro looking to take your business to the next level? Join the Pool Guy Coaching Program. Learn more at swimmingpoollearning.com. If you're looking for other podcasts, you go to my website, swingprolearning.com. And if you're interested in the coaching program that I offer can learn more at folkcoaching.com.  

Send us Fan Mail

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

Support the show

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