At what level would FC be considered “too high?”

[gdk64]

I read a great thread a few years back where Chem Geek gave expert advice. I don’t know if anything has changed since then, but wanted to revise that topic. (I do realize it’s a loaded question when you factor in CYA, etc.)

Generally speaking, I don’t think any health dept specifically states a max FC level, UNLESS their state has adopted the MAHC. All other HDs do defer to the chemical maker’s label and MSDS (which are all maxed with FC at 4ppm per EPA) for permitted levels. I wonder if any HD’s actually even check whether CYA is being monitored and whether some overstretched and uneducated pool management companies even understand be significance (or limits) of their CYA %.

Putting CYA aside for a moment, IS there a widely accepted max SAFE chlorine level (either FC or TC, anything at all?) for an outdoor swimming pool?

When we’re not trying to follow MAHC, and are using CYA, at what range are we talking “dangerous” or “potentially causing health risks” for people with chronic conditions?

We have a pool that flips and flops from 0 to >15ppm, with a CYA level nobody seems to know. Once the company was called out for not testing and then for not maintaining minimums, they’ve been maintaining FC levels consistently above 10ppm on a daily basis. This issue is now whether chlorine is “too high”, and our newly repainted feature kiddie pool is chipping away, and the chlorine seems unreasonably high.

Now, I don’t manage this particular pool, but I worry because lifeguards and bathers have both complained of health effects including skin burning and irritation, respiratory trouble, eye discomfort and blurriness, nausea, vomiting and diarrhea from chlorine being too high.

I’ve tried to speak to the manager (who I can’t seem to confirm if they are or aren’t actually licensed - where to look?), and unless chlorine is approaching 30ppm they “wouldn’t worry.” Up to 30 seems like a dangerous, unsafe and toxic level to accept as “safe.”

Can anyone tell me if there’s actually a “too high” level, in general?

WHO holds operators accountable when it’s “too high” if the HD only enforces a minimum?

For what it’s worth, I have a decent understanding of pool chemistry. The operator made comments that the chlorine (all pools are fed by automated meters) just needs to “burn off”, but with an unknown level of CYA, that seems improbable (and irresponsible to maintain when the system is functioning properly.)

Am I crazy? Thank you

 

[DrewLG]

Putting CYA aside for a moment, IS there a widely accepted max SAFE chlorine level (either FC or TC, anything at all?) for an outdoor swimming pool?

Of the compounds formed when chlorine reacts with pool water, HOCl is by far the most irritating and damaging (and disinfecting). The EPA's max of 4ppm FC with no CYA and 7.5 pH implies an HOCl concentration of around 2ppm. I'd personally call that a widely accepted maximum.

With CYA in the water, it's hard to get 2ppm HOCl. Even at SLAM level (FC concentration 40% of CYA concentration -- e.g. 20ppm FC with 50ppm CYA), the HOCl level is below 2ppm.

When we’re not trying to follow MAHC, and are using CYA, at what range are we talking “dangerous” or “potentially causing health risks” for people with chronic conditions?

The chloramines formed when chlorine oxidizes certain organic compounds can be very irritating to nose and lungs, but as far as I know (@JoyfulNoise would know for sure), chloramine production isn't really a function of FC concentration. For people with sensitive skin, I'd imagine that pH outside the normal range is more commonly than HOCl the cause of their issues.

Also, pools with inadequate sanitation -- too little FC -- can of course contain bacteria and other pathogens that irritate skin and cause health problems.

We have a pool .... with a CYA level nobody seems to know.

That's your largest problem (as you already know). Without measuring the CYA concentration, you can't know the HOCl concentration.