Safe Over SLAM Level?

[seven7seven]

Moved from HERE

As we are approaching this from an industry standpoint, perhaps an article in an industry publication would be a good place to start:

Aqua Magazine: CYA and Chlorine in Plain Language

IMO, the most important quote from that article is

Which means that 20 ppm CYA and 1 ppm FC is virtually the same as 200 ppm CYA and 10 ppm FC. With 3 ppm FC and zero CYA (perfectly safe and ideal according to the CDC) a body of water with pH of 7.5 at 80 degrees F would have an HOCl of 1.451. A pool with 2.5:1 CYA:FC concentration (SLAM Level) would have roughly 0.3 ppm HOCl. So a pool at SLAM level has only 1/5th the active chlorine (HOCl) as a pool that is within CDC guidance for safe and ideal. More chlorine can be less harsh, one of the most difficult things for anybody new to TFP to buy in to until it is experienced.

I will allow the rest of the article to speak for itself. Please keep in mind that the article, while following the same science TFP has been promoting for well over 10 years, was not written by anybody at TFP and may differ in some of the conclusions.

Sorry to revive an old thread, but what makes it unsafe to swim in a pool with FC higher than SLAM if SLAM is only 1/5 of the active chlorine level of the "perfectly safe 3ppm FC & 0 CYA from CDC"?

Given that logic I would have thought that the safe-to-swim level would be higher than SLAM.

P.S thank you for all the awesome info and help on TFP, I'm so thankful I found it!

 

[Texas Splash]

Good morning! Since you are referencing a discussion noted in the older thread (linked above), we should ensure @Donldson has the opportunity to reply regarding your question and the HOCI ratio. I'm sure he'll be happy to expand on your question next time he gets back online here with us. Thanks for posting your question,

 

[Bperry]

Moved from HERE


Sorry to revive an old thread, but what makes it unsafe to swim in a pool with FC higher than SLAM if SLAM is only 1/5 of the active chlorine level of the "perfectly safe 3ppm FC & 0 CYA from CDC"?

Given that logic I would have thought that the safe-to-swim level would be higher than SLAM.

P.S thank you for all the awesome info and help on TFP, I'm so thankful I found it!

Safe for swimmers is a different consideration than safe for pool liners, equipment, and clothing. The SLAM level chlorine is designed to have maximum sanitation power without causing damage to stuff contacting the water or wasting chlorine, not about whether there are health effects of being in it. The margin of safety is a different thing.

 

[Newdude]

+1. After finding the sweet spot for efficient algae killing, SLAM was tested and deemed safe for pools and swimmers. There was no need to test higher, but that doesn't mean that higher than SLAM isn't safe.