Should I be worried about brain eating amoeba / Naegleria fowleri

[coldpoolcanada]

Hey TFP,

For some reason ive always been paranoid about this so here goes:

So tested my pool 4 days ago at the pool store, and my TC & FC level was 10, CYA was 50, and PH was 7.4
Today my family and I swam a bit, after getting out I tested everything with at home strips. The chlorine level, it was 3 PPM, PH was 7.4.

Now looking at the chlorine/CYA chart, the minimum FC should be 4, is this a concern as mine was 3?
The pool is 29C, it is isolated (no continuous water fill) and I live in Toronto, Canada.
I am guessing the FC was above 4 in the days between the first test and now, and it hasn't really rained much so im not sure how it would be introduced.

Looking online it says that:

N. fowleri is susceptible to chlorine at concentrations of 0.5 and 1.0 mg/L (PPM)

Pathogen Safety Data Sheets: Infectious Substances – Naegleria fowleri - Canada.ca

These Pathogen Safety Data Sheets, regulated under Workplace Hazardous Materials Information System (WHMIS) legislation, are produced for personnel working in the life sciences as quick safety reference material relating to infectious micro-organisms.

www.canada.ca

However I assume this is at 0 CYA, at which the HOCL is 0.242
With my 50 CYA and 3 PPM Chlorine, I would be at 0.024
(Chart attached below)

Having a HOCL of 0.242 with CYA of 20 would require 8PPM, but the official CYA chart says that a minimum of 2PPM is allowed.

Why is there the discrepancy here?

 

[Newdude]

yes it's a thing. But no not really.

From 1962 to 2021 the US had 154 cases and only four survived, giving the disease a death rate of over 97%. Keep in mind that's across the country, including lakes, rivers, pools, etc.... for 59 years.


By comparison, in 2022 there were 124 automobile fatalities per *day* in the US. I'd be more worried an out of control car jumped into your pool while you swam.

Add some FC because you're flirting with min. Replace as much as you lose daily with some wiggle room in case it's particularly hot that day, a big storm rolls through, etc. Duck if you hear screeching tires.

If it *still* bothers you, ditch the unreliable pool store / test strips and order a Taylor K2006C.

 

[JJ_Tex]

Are you worried about it in your chlorinated pool...in Canada...filled by treated tap water?

The brain eating amoebas are real, but generally found in warm bodies of water like in the southern US. One of the rivers that feeds the lake where my parents are on is known to have the ameoba. The general warnings are posted to not swim in stagnant areas of the lake during the late summer months. Seems like common sense to me, but we did have to tell the kids to not use grandmas's lake swing in late summer months since her boathouse is on a canal leading to the lake so we didn't want to risk it. It lives in the muddy bottom, but we would still see lots of kids in the canals. There was one death from a kid on the lake ~20 years ago, so it is extremely rare even in a lake known to have the ameobas in them. Here is the link to their guidance, which is mainly common sense: As water heats up, so does the risk

I see no reason to worry unless your pool is unusually dirty, constantly underchlorinated, and you had some odd setup where you did not fill with treated water. Now, I have heard some stories about a new species of piranha that can get into your pool through the main drain... I would be more worried about that than the amoebas.

 

[coldpoolcanada]

Are you worried about it in your chlorinated pool...in Canada...filled by treated tap water?

The brain eating amoebas are real, but generally found in warm bodies of water like in the southern US. One of the rivers that feeds the lake where my parents are on is known to have the ameoba. The general warnings are posted to not swim in stagnant areas of the lake during the late summer months. Seems like common sense to me, but we did have to tell the kids to not use grandmas's lake swing in late summer months since her boathouse is on a canal leading to the lake so we didn't want to risk it. It lives in the muddy bottom, but we would still see lots of kids in the canals. There was one death from a kid on the lake ~20 years ago, so it is extremely rare even in a lake known to have the ameobas in them. Here is the link to their guidance, which is mainly common sense: As water heats up, so does the risk

I see no reason to worry unless your pool is unusually dirty, constantly underchlorinated, and you had some odd setup where you did not fill with treated water. Now, I have heard some stories about a new species of piranha that can get into your pool through the main drain... I would be more worried about that than the amoebas.

haha, it does seem silly now. The water is filled from an untreated (cold) well water from time to time, but the chlorine level has been 10PPM at that time, well above the 4PPM min as shown on the chlorine/CYA chart.
I am still curious on the 0.5PPM they gave and how that relates to CYA/ HOCl in pool.

Thanks for the response, and ill keep an eye out for piranhas

 

[sande005]

The discrepancy is both due to what is being treated for, and time. The charts were primarily intended as a guide to prevent algae from growing. I suspect that the amoeba might be susceptible to a lower level, if exposed long enough. But that thesis would have to be researched.
If it makes you feel better (or worse), water from your tap has a good chance of being at 0 ppm Cl. It started its journey to you at a higher level...but who knows how many meters/kilometers of pipe have water flowing with all the FC used up....

 

[coldpoolcanada]

The discrepancy is both due to what is being treated for, and time. The charts were primarily intended as a guide to prevent algae from growing. I suspect that the amoeba might be susceptible to a lower level, if exposed long enough. But that thesis would have to be researched.
If it makes you feel better (or worse), water from your tap has a good chance of being at 0 ppm Cl. It started its journey to you at a higher level...but who knows how many meters/kilometers of pipe have water flowing with all the FC used up....

Yea it’s sensitive to chlorine from what I see;

The amoeba of Naegleria fowleri is sensitive to chlorine. One ppm of free chlorine will kill 99.9% (a 3-log kill) of the amoeba in 9 minutes (CT=9). This low CT value verifies that the infective amoeba of this organism will not survive in a properly chlorinated swimming pool or spa.

Although they don’t provide a CYA level.
And yea my tap water is from a cold well in my yard but it’s probably too cold for any amoebas to live in