January 1, 2026 • 23 mins
Most pool pros have heard it for years: lower the pH to make chlorine stronger. That’s true in non-stabilized water, but once cyanuric acid enters the picture, the rules change. We sit down with Eric Knight to unpack why the FC-to-CYA ratio, not pH, governs chlorine’s effective strength in outdoor pools—and how that insight can save you time, money, and a lot of acid.
We break down the chemistry in plain language. You’ll hear how chlorine splits into hypochlorous acid and hypochlorite ion, why that balance matters indoors, and how CYA binds most chlorine outdoors to form isocyanurates. With typical CYA levels, the effective kill speed stays nearly the same between pH 7.0 and 8.0, which means chasing an ultra-low pH for “stronger chlorine” is a dead end. Instead, use pH to manage balance on the Langelier Saturation Index, contain its rise with smart alkalinity and calcium hardness, and aim for a CYA level that keeps your free chlorine target achievable.
We also talk real-world strategy: the pitfalls of overstabilization, how high CYA inflates contact times, and why partial drains are sometimes the only fix. To sharpen your program, support chlorine with enzymes to trim oxidant demand, control phosphates to lower growth pressure, and consider secondary oxidation where it fits. The goal is a stable chain: CYA in range, free chlorine matched to that CYA, pH contained for LSI, and demand reduced so sanitizer can do its job.
• FC-to-CYA ratio as the primary driver of chlorine effectiveness in outdoor pools
• Why pH control matters for LSI balance more than sanitization with CYA present
• The equilibrium of HOCl and OCl− in non-stabilized water contrasted with CYA-bound chlorine
• Practical CYA ranges and why levels above 50 ppm complicate free chlorine targets
• Overstabilization risks, longer contact times, and when to drain and dilute
• Using enzymes, phosphate control, and secondary oxidizers to reduce oxidant demand
• Containing pH with LSI strategy instead of forcing low numbers that rebound
• Clear differences between sa
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Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
SPEAKER_01 (01:50):
Hey, welcome to the Full Black Podcast Show.
As I enter my tenth season ornine years of doing this podcast
show, at the end of this year,it'll be my tenth, tenth year
doing the podcast.
I want to thank everyone forsticking with me throughout the
years, and the tenth season ofthe show will allow me to cross
the 2 million download mark,which is a true milestone in
(02:13):
podcasting.
So again, I want to thank you,the loyal listeners of the Pool
Guy Podcast Show.
In today's episode, I'm going togo back to 2020, where I
interviewed Eric Knight, then ofOrenda and Hassa.
He's now the executive directorof Waterscape University.
And he's going to talk about therelationship between your
(02:37):
planeric acid and the pH in thepool.
And it's a really interestingtalk that I think is really
relevant today.
And so let's kick off the 10thseason of the Pool Guy Podcast
show.
Are you a Pool Service prolooking to take your business to
the next level?
Join the Pool Guy CoachingProgram.
Get expert advice, businesstips, exclusive content, and get
(02:58):
direct support from me.
I'm a 35-year veteran in theindustry.
Whether you're starting out orscaling up, I've got the tools
to help you succeed.
Learn more at swimmingpoollearning.com.
Uh thanks for joining me today.
We're going to be talking aboutkind of a complex subject.
It's the relationship betweenpH, chlorine, and cyaneric acid.
And I'll start with the firstquestion here.
(03:20):
And if you could just explainbriefly the relationship between
pH and chlorine's effectiveness.
SPEAKER_02 (03:26):
Sure.
So when chlorine goes intowater, no matter what type of
chlorine you use, trichlor,liquid chlorine, calhypo, uh,
what happens is you get thisdissociation reaction where
hydrogen either binds to it orleaves it.
And what happens is you have twodifferent types of chlorine.
You've got the strong killingform of chlorine called
(03:49):
hypochlorous acid.
And then you've got the weaker,like a hundred or more times
slower and weaker form calledthe hypochlorite ion.
And these two are alwaysfunctioning in an equilibrium,
either 50-50, 60-40, 70-30 atall times.
And the pH controls that ratio.
(04:11):
So the lower your pH, the higherthe percentage of the strong
killing form of chlorine.
And it's the opposite, thehigher the pH, the lower that
percentage.
So the higher your pH, theweaker your chlorine.
But all of that only applies toa non-stabilized pool.
And this is the trap because somany people in the pool business
(04:35):
have always been taught that thepH must be lower to have
stronger chlorine.
And that's true if there's nostabilizer.
But David, how many outdoorpools do you know of that have
zero stabilizer in them?
SPEAKER_01 (04:48):
Yeah, none.
SPEAKER_02 (04:49):
Pretty much none.
I mean, in the state of NewYork, the commercial ones don't,
but let's be realistic, thiskind of goes out the window
because the strength of chlorineis now commanded by the free
chlorine to cyaneric acid ratio,which I think we're probably
about to discuss.
SPEAKER_01 (05:06):
Yeah.
So this the next question is umlet's add the variable of
cyaneric acid into the equationnow.
Um how does that change therelationship between pH and
chlorine's effectiveness?
SPEAKER_02 (05:17):
So uh I have a chart here, if I can share my screen
uh so that your viewers can seeit.
So let me share my screen.
SPEAKER_01 (05:25):
And for those of you who are listening to the YouTube
version of this, you're gonnasee the chart appear in the
video here.
And if you're listening to thepodcast, you can find this chart
very easily.
I have it in a Google Drivefile.
You can get to the link for theimage while you're listening to
the podcast by in the Googlesearch box.
You just have to type in rb.gyforward slash G Z O R R E.
(05:54):
Again, that's rb.gy forwardslash G Z O R R E.
And that should take you to theGoogle Drive file of the image
that um Eric is talking aboutright now in the podcast.
SPEAKER_02 (06:11):
And let me know if you can see this chart.
SPEAKER_01 (06:14):
Yeah, I can see it.
SPEAKER_02 (06:15):
Okay, so the left side, as I was just explaining,
the red line uh is hypochlorousacid, HOCL.
The lower the pH, the higher thepercentage, stronger chlorine.
So at 7.2, it's uh about 65 to66 percent, it looks like, of
strong chlorine.
The rest, a much lowerpercentage of weak chlorine.
(06:38):
But up here at like 7.8 or 7.9,it's a much higher percentage of
the weak chlorine, you know,over a hundred times slower and
weaker, this hypochlorite ion,which is this green line OCL
negative.
This is what we're all used to.
At around 7.5, it's 5050.
But that's with no stabilizer.
(07:00):
So, to your question, withstabilizer, let's come over to
the right side.
Now find the red line.
David, do you see it?
SPEAKER_01 (07:08):
Yeah, at the bottom.
SPEAKER_02 (07:09):
At the bottom.
And at 7.0 pH, it's about 3%, asopposed to here, where it's 75%
without stabilizer.
Now it's about 3% with 30 partsper million CYA.
And most outdoor pools have morethan 30 parts per million CYA
anyway.
So can you really tell thedifference between 70 pH and 80
(07:33):
pH on this chart with the redline?
SPEAKER_01 (07:36):
No, it's pretty equal.
SPEAKER_02 (07:38):
It's pretty equal.
I mean, it goes down a littlebit, but it's less than 1%
difference.
So it's it's pretty muchnegligible.
And that is what we determine asthe strength.
I'm using air quotes, thestrength of chlorine is actually
remarkably the same between 7.0and 8.0 pH, and even up to 8.5,
(07:59):
8.6, if you look at that chart.
And that's because the vastmajority of the chlorine has
been bound up by cyanuric acid,which is this blue line at the
very top.
So now these are, I thinkthey're called isocyanurates.
This is basically chlorineattached to cyanuric acid.
This is the vast majority ofwhat is in your pool.
It's not all bad though, becauseI know it looks like your
(08:21):
chlorine, oh my gosh, it's soweak.
You know, it's it's only 3%.
That's not necessarily true.
What only matters here is thedifference between the different
pHs.
The pH no longer controls theswing, is what I'm trying to get
at.
Because you do have plenty ofchlorine, it is slowed down
(08:43):
because it has to release itselffrom cyanuric acid to go oxidize
or sanitize.
So that's what I'm trying to getat is stabilizer stabilizer
takes over, whereas pH no longercontrols the strength or speed
of your chlorine, stabilizerdoes.
SPEAKER_01 (09:03):
Got it.
So all the guys that are tryingto keep their pH at 7.2 to make
the chlorine much more effectiveor faster at killing um the
viruses, germs, bacteria in thewater with the cyaneric acid in
there, there's no real reason tokeep it down at 7.2 because at
8.0 with 30 parts per millionaccording to this chart, the
(09:23):
chlorine's going to have thesame killing speed no matter
what the pH is.
Is that correct?
SPEAKER_02 (09:28):
Or very close to it.
I mean, there are it doesslightly go down, but it's
negligible difference.
So you look here.
I mean, here's 7.2.
Can you even see a differencebetween 7.2 and 8.0 in terms of
the strength of chlorine?
SPEAKER_01 (09:40):
Very very small percentage.
So the guys that are justthinking, like uh the old school
thinking like myself, that thepH is a big factor in the
chlorine's killing ability, um,that becomes kind of that kind
of throws it out the window whenyou look at this chart with 30
parts per million of cyanericacid in it.
So we're actually probablywasting money, time, and effort
(10:02):
trying to keep the pH low allthe time in the pool.
Sure.
SPEAKER_02 (10:07):
Uh that's certainly the case.
And uh that chart, by the way,is all available on our blog,
which is blog.orendatech.com.
There's a search bar, just typein CYA and hit enter, and you
will see uh we probably have 10articles about it.
That chart's in a lot of thosearticles.
(10:27):
I think there's kind of twosides to what you just said.
When people are trying tocorrect pH, don't be correcting
pH because of the strength ofchlorine.
There are reasons to adjust pH,but I think the mistake that we
see most often is people try tocontrol pH.
It doesn't want to becontrolled.
pH is a reactionary chemistry,it's going to bounce away from
(10:50):
you like a rabbit.
So instead, what we want to dois we want to teach people to
try to contain pH.
Use things like the LSI to youradvantage and understand that
physics is going to pull the pHup to 8.2 anyway.
So if you know where the ceilingis and you can set the floor
with something like calciumhardness, you can contain the
(11:12):
pH.
So my message to your viewers isdon't necessarily lower your pH
to 7.4 below just for the sakeof thinking it's for chlorine.
It's not anymore.
Maybe go to 7.6 and have more ofan LSI-based strategy because
the pH dramatically impacts theLSI, which is the saturation
(11:34):
index.
And one thing I'd like to tagonto that is there are really
two sides to water chemistry.
There's sanitization, which iskeeping the pool clean, clear,
algae-free, chlorination,safety, all that stuff.
And then there's balance.
And people conflate the terms.
They think, oh, my chemistry isbalanced because I have a lot of
(11:55):
chlorine in there.
They're largely unrelated.
Balance is the saturation ofcalcium carbonate as measured on
the LSI, or if you choose, youcould use like a Hamilton index
or Reisner.
That's balance.
And pH is really, really, reallyimportant for balance.
It is not important for uhsanitization in a cyanuric acid
(12:18):
pool.
But say an indoor commercialpool that has no stabilizer in
it, yes, pH controls thechlorine strength directly.
So it's it's still veryimportant there.
SPEAKER_01 (12:27):
Yeah, so I'll just we'll touch on that one more
time.
When you say balance, so the LSIwill indicate if the pool is
corrosive or if the pool isscale forming, and pH is one of
the factors in that.
I don't want to I don't want togloss over that.
So people know that youmentioned that just by balancing
the water, people think sincethey have sanitizer in the pool,
that the water is safe andbalanced, but it's not really
(12:49):
balanced in the way of the LSI,where it could be a corrosive
water versus a scale-formingwater.
SPEAKER_02 (12:56):
Yes, you you could have you could have a safe,
clean pool that's horribly outof balance, and you could have a
green, disgusting, algae-filledpool that's perfectly balanced.
I mean, it's not likely, but Imean it's possible.
So it we have to look at thosethings as two different things.
So for your homeowners who arelistening, or the pool service
(13:17):
guys, if you have aggressivewater on the LSI, this is the
water that destroys surfaces byetching, it destroys heat
exchangers, salt cells, uh, itdestroys vinyl liners.
They start fading and cracking.
Same with fiberglass pools.
Aggressive water is hungry forone thing and one thing only.
(13:37):
Do you know what that one thingis?
Calcium's and it will stop atnothing to find it.
So that's balanced, right?
So we don't want to confuse thetwo.
And so, yeah, I don't thinkgoing down to 7.4 is necessary
because the pH is trying to getup to 8.2.
That's a huge swing on the LSI.
(13:58):
You're gonna be a lot better offgoing down only 7.6 or even 7.7
and letting that pH rise a lotslower because it's closer to
its end goal.
SPEAKER_01 (14:09):
Okay, and so you know, the biggest takeaway, I
think, from this for thelisteners is that you should
look at pH more as a balancingtool for the LSI versus if this
is speaking of a pool withcyaneric acid in it, of course,
uh, versus one as an indoor poolwithout it.
So if the pool has cyaneric acidin it as a stabilizer, you're
looking more for pH to notcontrol the effectiveness of
(14:32):
chlorine, because now the chartshowed us that with the cyaneric
acid level at 30 parts amillion, there's not a lot of
difference in the kill speed at7.0 and 8.0.
So what you should be doing asfar as adding acid to lower the
pH down is for the LSI balancingand not necessarily to increase
the effectiveness or the killrate of the chlorine.
SPEAKER_02 (14:52):
Correct.
The the ways that you optimizethe killing effectiveness of
chlorine is to manage the freechlorine to cyanuric acid ratio.
And and that is what reallymatters in terms of
sanitization.
And then outside of that, youcan remove the oxidant demand
with enzymes or a secondaryoxidizer like ozone, and you can
(15:14):
remove nutrients like phosphatesthat slow down the growth and
reproductive rate ofcontaminants.
But really, when it comes tosanitizer, you what really
controls chlorine effectivenessis cyanuric acid.
SPEAKER_01 (15:28):
And you know, I'm a big fan of chlorine enhancers
nowadays.
I I've I really jumped in abandwagon.
I was an old school pool guythat I didn't really pay much
attention to it or or give itmuch credence.
But I think by enhancing theeffectiveness of free free
chlorine, especially with the inlieu of the chart you showed
about the cyaneric acid levelinterfering with the kill rate
(15:49):
of the chlorine, I think byenhancing that free chlorine by
using enzymes and phosphates isa key factor in maintaining a
good balanced pool, balanced inthe and in the way of sanitizer
being effective.
Um and I think a lot of poolprofessionals are starting to
realize that that the guys thatwere ignoring the chlorine
enhancers are starting to seethe the need for it.
(16:10):
And the chart really illustratesthe fact that pH can no longer
be um the key element in makingchlorine effective.
It's just the free chlorine iswhat is what we should be
focusing on.
SPEAKER_02 (16:23):
Well, you're you're right.
Well, the free chlorine tocyanuric acid ratio.
And I just want to say that wedidn't make any of this up.
Um Renda certainly didn't.
We didn't even do any of theresearch directly.
Uh I just read from people whohave done the science, uh,
people like Richard Falk and Dr.
Alan Meyer and the council adhoc committee for the Model
Aquatic Health Code, all theselittle acronyms of these
(16:45):
agencies that are doing thisresearch for the industry.
All I'm trying to do is be themessenger and distill this
information.
I didn't make up the chart, butwhen I ask the people who did
make the chart what it means, isit's a paradigm shift, guys.
We have to think a little bitdifferently here.
Cyaneric acid has a lot ofbenefits to it, but too much
(17:06):
cyaneric acid doesn't give youany more sunlight protection,
but it's all the detriments thatgo with overstabilization.
So that's what we want to avoid.
We want to avoid too much CYA.
We don't want to have none.
SPEAKER_01 (17:26):
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(17:49):
Yeah, so look the person thathas a pool with a cyaneric acid
of 100-150 parts per million,they're gonna have a harder
time, especially with thatchart.
It was only at 30 parts permillion on that chart.
So I can imagine at 150 partsper million, how slow is that
chlorine's effectiveness?
SPEAKER_02 (18:05):
Well, it that's a great question.
I don't know the answer.
I'm sure there's parts that cando it, and you can extrapolate.
If you look at the data um andthere's a lot of data available,
there's charts that show thekill time, or the it's called
CT, contact time.
And it goes up a lot.
I'm not sure if it'sexponentially, but for instance,
(18:27):
Cryptosporidium is a verychlorine-resistant bug that
commercial pools really have toworry about in case there's like
a diarrheal accident with achild.
That problem can shut down anentire swimming pool and they
have to be forced to drain.
So the CDC gets involved andthey look at the cyanuric acid,
(18:48):
and they came up with a uh, Idon't know if it's a regulation,
but basically a limit, apractical limit that if you have
more than 15 parts per million,15, 1.5 parts per million CYA,
you have to drain your pool downto below 15 parts before you can
effectively sanitize it becauseyou couldn't even measure the
(19:10):
contact time required.
So it goes, it goes through theroof the higher your CYA.
And it's not linear, it's it'sit's kind of parabolic.
It goes up really fast thehigher and higher you go.
So if you have a hundred see 150CYA or above, there's really
only one thing Arenda wouldrecommend you do, and that's
drain a portion of your pool, ifnot all of it, to get that that
(19:33):
number down because it's it'sgot total control over your pool
at that point.
SPEAKER_01 (19:37):
Yeah, it's interesting.
I really think that the CYA, umsome people call it a debate in
the industry, but there's reallynot much debate if you look at
the data.
The higher the CYA, the moreproblems you're gonna have with
everything.
And not only that, but you haveto have a higher free chlorine
level and with the highercyaneric acid level.
So um all those are huge factorsin this.
(19:57):
Um so someone listening to thispodcast, where can they go to
get more information about uhthe chart that you showed, um,
all this all the educational uhmaterial that Arenda makes?
SPEAKER_02 (20:09):
Certainly.
Uh you can access all of itthrough the Arenda app, which is
a free app.
It's available in the Play Storeand uh the Apple Store.
Um in the menu you can seearticles.
You can search C Y A and get toit.
That taps into our blog on ourwebsite.
If you prefer on a desktop, youcan just go to our website
(20:30):
orendatech.com,O-R-E-N-D-A-T-E-C-H dot com.
Tap on the blog, all theinformation is there.
Type C Y A in the search bar,you'll see all the cyaneric acid
uh articles about it.
We've got 10 or more, I think.
We have a lot of videos aboutCYA as well where we explain
this.
And again, this data does notcome from us, so we hyperlink
(20:52):
out to our sources so you cansee it for yourself.
Um but you know, the opinionsthat I've shared today have been
vetted because I've spoken tothe people who wrote the charts,
and I've I I understand whatthey're trying to say in the
charts because they can be kindof intimidating to look at
without any context.
So, what I explained to youtoday is accurate to the best of
(21:13):
our knowledge.
And if anything like thatchanges, I'll be sure to update
our blog or anything else.
Because you know, sometimes whenthere's something new like this,
you gotta take the time to slowdown and make sure that it is
accurate and everyone's sureabout it.
This is pretty settled, it seemslike.
SPEAKER_01 (21:32):
Yeah, I think so.
I I think you know the adjustedaquinity thing has been
something.
That it's pretty much settlednow, too.
And that was pretty new for awhile there, too.
And I think cyaneric acid issomething that as an industry,
um, it's like a double-edgedstore.
We do need it because we can'tbe at the account every day to
add chlorine to the pool, likeback in the 50s or 60s.
(21:54):
I don't know when pools werestarted, run out of time.
Um, but you also you have torealize that this is something
that will bind up the chlorinein the pool, and there's got to
be some kind of effect withthat.
It's not something that you canignore as a factor.
SPEAKER_02 (22:09):
Yeah, and again, you it's stabilizer itself is not
the problem.
Over stabilization is theproblem.
It's too much, right?
Because if you have a goodratio, you get sunlight
protection, chlorine is stillfast enough to do its job, you
know, it's all good.
And that this is neg this isdebatable.
You could make an argumenteither way.
(22:30):
Arenda's opinion, the optimallevel is around 30 parts per
million, 15 to 30.
Uh, you can go as high as youwant.
After 50, it gets really hard.
After above 50 parts per millionCYA, it's very hard to maintain
enough free chlorine to keepthat ratio optimal.
But I mean, you can you can doit.
(22:51):
If you want 100 parts, okay, butyou got to maintain 7.5 parts
per million free chlorine allweek.
Good luck.
That's that's a really highnumber of chlorine.
But back to what I was sayingearlier, to kind of pull this
together, there's two sides towater chemistry, right?
There's sanitization, keeping itclean, healthy, all that stuff,
chlorination, and then there'sbalance.
(23:13):
Cyanuric acid dramaticallyimpacts both.
There's only a few other factorsthat do.
For instance, pH impacts both,but with cyanuric acid, pH is
kind of almost negligible on thesanitization thing.
Uh without CYA, of course, it'svery important.
But what does calcium hardnesshave to do with sanitization?
unknown (23:34):
Right?
SPEAKER_02 (23:35):
What does TDS have to do with sanitization?
Not that much.
But cyanuric acid is profound onboth sides of water chemistry.
So we have to maintain levelsthat can be managed.
SPEAKER_01 (23:47):
Yeah.
Well, I appreciate that, Eric.
And I thank you for your time todiscuss this and to really
unpack it in the understandableway for the listeners.
And if you're looking for otherepisodes, of course, you can go
to my website, swinging forlearning.com, and you're gonna
see about eighteen hundredepisodes available.
Just click on the podcast iconand the banner.
And if you're interested in thecoaching program that I offer,
(24:08):
you can learn more atPoolGuyCoaching.com.
Thanks for listening to thispodcast.
Have your rest of your week andGod bless.
Hey, welcome to the Full Black Podcast Show.
As I enter my tenth season ornine years of doing this podcast
show, at the end of this year,it'll be my tenth, tenth year
doing the podcast.
I want to thank everyone forsticking with me throughout the
years, and the tenth season ofthe show will allow me to cross
the 2 million download mark,which is a true milestone in
(02:13):
podcasting.
So again, I want to thank you,the loyal listeners of the Pool
Guy Podcast Show.
In today's episode, I'm going togo back to 2020, where I
interviewed Eric Knight, then ofOrenda and Hassa.
He's now the executive directorof Waterscape University.
And he's going to talk about therelationship between your
(02:37):
planeric acid and the pH in thepool.
And it's a really interestingtalk that I think is really
relevant today.
And so let's kick off the 10thseason of the Pool Guy Podcast
show.
Are you a Pool Service prolooking to take your business to
the next level?
Join the Pool Guy CoachingProgram.
Get expert advice, businesstips, exclusive content, and get
(02:58):
direct support from me.
I'm a 35-year veteran in theindustry.
Whether you're starting out orscaling up, I've got the tools
to help you succeed.
Learn more at swimmingpoollearning.com.
Uh thanks for joining me today.
We're going to be talking aboutkind of a complex subject.
It's the relationship betweenpH, chlorine, and cyaneric acid.
And I'll start with the firstquestion here.
(03:20):
And if you could just explainbriefly the relationship between
pH and chlorine's effectiveness.
SPEAKER_02 (03:26):
Sure.
So when chlorine goes intowater, no matter what type of
chlorine you use, trichlor,liquid chlorine, calhypo, uh,
what happens is you get thisdissociation reaction where
hydrogen either binds to it orleaves it.
And what happens is you have twodifferent types of chlorine.
You've got the strong killingform of chlorine called
(03:49):
hypochlorous acid.
And then you've got the weaker,like a hundred or more times
slower and weaker form calledthe hypochlorite ion.
And these two are alwaysfunctioning in an equilibrium,
either 50-50, 60-40, 70-30 atall times.
And the pH controls that ratio.
(04:11):
So the lower your pH, the higherthe percentage of the strong
killing form of chlorine.
And it's the opposite, thehigher the pH, the lower that
percentage.
So the higher your pH, theweaker your chlorine.
But all of that only applies toa non-stabilized pool.
And this is the trap because somany people in the pool business
(04:35):
have always been taught that thepH must be lower to have
stronger chlorine.
And that's true if there's nostabilizer.
But David, how many outdoorpools do you know of that have
zero stabilizer in them?
SPEAKER_01 (04:48):
Yeah, none.
SPEAKER_02 (04:49):
Pretty much none.
I mean, in the state of NewYork, the commercial ones don't,
but let's be realistic, thiskind of goes out the window
because the strength of chlorineis now commanded by the free
chlorine to cyaneric acid ratio,which I think we're probably
about to discuss.
SPEAKER_01 (05:06):
Yeah.
So this the next question is umlet's add the variable of
cyaneric acid into the equationnow.
Um how does that change therelationship between pH and
chlorine's effectiveness?
SPEAKER_02 (05:17):
So uh I have a chart here, if I can share my screen
uh so that your viewers can seeit.
So let me share my screen.
SPEAKER_01 (05:25):
And for those of you who are listening to the YouTube
version of this, you're gonnasee the chart appear in the
video here.
And if you're listening to thepodcast, you can find this chart
very easily.
I have it in a Google Drivefile.
You can get to the link for theimage while you're listening to
the podcast by in the Googlesearch box.
You just have to type in rb.gyforward slash G Z O R R E.
(05:54):
Again, that's rb.gy forwardslash G Z O R R E.
And that should take you to theGoogle Drive file of the image
that um Eric is talking aboutright now in the podcast.
SPEAKER_02 (06:11):
And let me know if you can see this chart.
SPEAKER_01 (06:14):
Yeah, I can see it.
SPEAKER_02 (06:15):
Okay, so the left side, as I was just explaining,
the red line uh is hypochlorousacid, HOCL.
The lower the pH, the higher thepercentage, stronger chlorine.
So at 7.2, it's uh about 65 to66 percent, it looks like, of
strong chlorine.
The rest, a much lowerpercentage of weak chlorine.
(06:38):
But up here at like 7.8 or 7.9,it's a much higher percentage of
the weak chlorine, you know,over a hundred times slower and
weaker, this hypochlorite ion,which is this green line OCL
negative.
This is what we're all used to.
At around 7.5, it's 5050.
But that's with no stabilizer.
(07:00):
So, to your question, withstabilizer, let's come over to
the right side.
Now find the red line.
David, do you see it?
SPEAKER_01 (07:08):
Yeah, at the bottom.
SPEAKER_02 (07:09):
At the bottom.
And at 7.0 pH, it's about 3%, asopposed to here, where it's 75%
without stabilizer.
Now it's about 3% with 30 partsper million CYA.
And most outdoor pools have morethan 30 parts per million CYA
anyway.
So can you really tell thedifference between 70 pH and 80
(07:33):
pH on this chart with the redline?
SPEAKER_01 (07:36):
No, it's pretty equal.
SPEAKER_02 (07:38):
It's pretty equal.
I mean, it goes down a littlebit, but it's less than 1%
difference.
So it's it's pretty muchnegligible.
And that is what we determine asthe strength.
I'm using air quotes, thestrength of chlorine is actually
remarkably the same between 7.0and 8.0 pH, and even up to 8.5,
(07:59):
8.6, if you look at that chart.
And that's because the vastmajority of the chlorine has
been bound up by cyanuric acid,which is this blue line at the
very top.
So now these are, I thinkthey're called isocyanurates.
This is basically chlorineattached to cyanuric acid.
This is the vast majority ofwhat is in your pool.
It's not all bad though, becauseI know it looks like your
(08:21):
chlorine, oh my gosh, it's soweak.
You know, it's it's only 3%.
That's not necessarily true.
What only matters here is thedifference between the different
pHs.
The pH no longer controls theswing, is what I'm trying to get
at.
Because you do have plenty ofchlorine, it is slowed down
(08:43):
because it has to release itselffrom cyanuric acid to go oxidize
or sanitize.
So that's what I'm trying to getat is stabilizer stabilizer
takes over, whereas pH no longercontrols the strength or speed
of your chlorine, stabilizerdoes.
SPEAKER_01 (09:03):
Got it.
So all the guys that are tryingto keep their pH at 7.2 to make
the chlorine much more effectiveor faster at killing um the
viruses, germs, bacteria in thewater with the cyaneric acid in
there, there's no real reason tokeep it down at 7.2 because at
8.0 with 30 parts per millionaccording to this chart, the
(09:23):
chlorine's going to have thesame killing speed no matter
what the pH is.
Is that correct?
SPEAKER_02 (09:28):
Or very close to it.
I mean, there are it doesslightly go down, but it's
negligible difference.
So you look here.
I mean, here's 7.2.
Can you even see a differencebetween 7.2 and 8.0 in terms of
the strength of chlorine?
SPEAKER_01 (09:40):
Very very small percentage.
So the guys that are justthinking, like uh the old school
thinking like myself, that thepH is a big factor in the
chlorine's killing ability, um,that becomes kind of that kind
of throws it out the window whenyou look at this chart with 30
parts per million of cyanericacid in it.
So we're actually probablywasting money, time, and effort
(10:02):
trying to keep the pH low allthe time in the pool.
Sure.
SPEAKER_02 (10:07):
Uh that's certainly the case.
And uh that chart, by the way,is all available on our blog,
which is blog.orendatech.com.
There's a search bar, just typein CYA and hit enter, and you
will see uh we probably have 10articles about it.
That chart's in a lot of thosearticles.
(10:27):
I think there's kind of twosides to what you just said.
When people are trying tocorrect pH, don't be correcting
pH because of the strength ofchlorine.
There are reasons to adjust pH,but I think the mistake that we
see most often is people try tocontrol pH.
It doesn't want to becontrolled.
pH is a reactionary chemistry,it's going to bounce away from
(10:50):
you like a rabbit.
So instead, what we want to dois we want to teach people to
try to contain pH.
Use things like the LSI to youradvantage and understand that
physics is going to pull the pHup to 8.2 anyway.
So if you know where the ceilingis and you can set the floor
with something like calciumhardness, you can contain the
(11:12):
pH.
So my message to your viewers isdon't necessarily lower your pH
to 7.4 below just for the sakeof thinking it's for chlorine.
It's not anymore.
Maybe go to 7.6 and have more ofan LSI-based strategy because
the pH dramatically impacts theLSI, which is the saturation
(11:34):
index.
And one thing I'd like to tagonto that is there are really
two sides to water chemistry.
There's sanitization, which iskeeping the pool clean, clear,
algae-free, chlorination,safety, all that stuff.
And then there's balance.
And people conflate the terms.
They think, oh, my chemistry isbalanced because I have a lot of
(11:55):
chlorine in there.
They're largely unrelated.
Balance is the saturation ofcalcium carbonate as measured on
the LSI, or if you choose, youcould use like a Hamilton index
or Reisner.
That's balance.
And pH is really, really, reallyimportant for balance.
It is not important for uhsanitization in a cyanuric acid
(12:18):
pool.
But say an indoor commercialpool that has no stabilizer in
it, yes, pH controls thechlorine strength directly.
So it's it's still veryimportant there.
SPEAKER_01 (12:27):
Yeah, so I'll just we'll touch on that one more
time.
When you say balance, so the LSIwill indicate if the pool is
corrosive or if the pool isscale forming, and pH is one of
the factors in that.
I don't want to I don't want togloss over that.
So people know that youmentioned that just by balancing
the water, people think sincethey have sanitizer in the pool,
that the water is safe andbalanced, but it's not really
(12:49):
balanced in the way of the LSI,where it could be a corrosive
water versus a scale-formingwater.
SPEAKER_02 (12:56):
Yes, you you could have you could have a safe,
clean pool that's horribly outof balance, and you could have a
green, disgusting, algae-filledpool that's perfectly balanced.
I mean, it's not likely, but Imean it's possible.
So it we have to look at thosethings as two different things.
So for your homeowners who arelistening, or the pool service
(13:17):
guys, if you have aggressivewater on the LSI, this is the
water that destroys surfaces byetching, it destroys heat
exchangers, salt cells, uh, itdestroys vinyl liners.
They start fading and cracking.
Same with fiberglass pools.
Aggressive water is hungry forone thing and one thing only.
(13:37):
Do you know what that one thingis?
Calcium's and it will stop atnothing to find it.
So that's balanced, right?
So we don't want to confuse thetwo.
And so, yeah, I don't thinkgoing down to 7.4 is necessary
because the pH is trying to getup to 8.2.
That's a huge swing on the LSI.
(13:58):
You're gonna be a lot better offgoing down only 7.6 or even 7.7
and letting that pH rise a lotslower because it's closer to
its end goal.
SPEAKER_01 (14:09):
Okay, and so you know, the biggest takeaway, I
think, from this for thelisteners is that you should
look at pH more as a balancingtool for the LSI versus if this
is speaking of a pool withcyaneric acid in it, of course,
uh, versus one as an indoor poolwithout it.
So if the pool has cyaneric acidin it as a stabilizer, you're
looking more for pH to notcontrol the effectiveness of
(14:32):
chlorine, because now the chartshowed us that with the cyaneric
acid level at 30 parts amillion, there's not a lot of
difference in the kill speed at7.0 and 8.0.
So what you should be doing asfar as adding acid to lower the
pH down is for the LSI balancingand not necessarily to increase
the effectiveness or the killrate of the chlorine.
SPEAKER_02 (14:52):
Correct.
The the ways that you optimizethe killing effectiveness of
chlorine is to manage the freechlorine to cyanuric acid ratio.
And and that is what reallymatters in terms of
sanitization.
And then outside of that, youcan remove the oxidant demand
with enzymes or a secondaryoxidizer like ozone, and you can
(15:14):
remove nutrients like phosphatesthat slow down the growth and
reproductive rate ofcontaminants.
But really, when it comes tosanitizer, you what really
controls chlorine effectivenessis cyanuric acid.
SPEAKER_01 (15:28):
And you know, I'm a big fan of chlorine enhancers
nowadays.
I I've I really jumped in abandwagon.
I was an old school pool guythat I didn't really pay much
attention to it or or give itmuch credence.
But I think by enhancing theeffectiveness of free free
chlorine, especially with the inlieu of the chart you showed
about the cyaneric acid levelinterfering with the kill rate
(15:49):
of the chlorine, I think byenhancing that free chlorine by
using enzymes and phosphates isa key factor in maintaining a
good balanced pool, balanced inthe and in the way of sanitizer
being effective.
Um and I think a lot of poolprofessionals are starting to
realize that that the guys thatwere ignoring the chlorine
enhancers are starting to seethe the need for it.
(16:10):
And the chart really illustratesthe fact that pH can no longer
be um the key element in makingchlorine effective.
It's just the free chlorine iswhat is what we should be
focusing on.
SPEAKER_02 (16:23):
Well, you're you're right.
Well, the free chlorine tocyanuric acid ratio.
And I just want to say that wedidn't make any of this up.
Um Renda certainly didn't.
We didn't even do any of theresearch directly.
Uh I just read from people whohave done the science, uh,
people like Richard Falk and Dr.
Alan Meyer and the council adhoc committee for the Model
Aquatic Health Code, all theselittle acronyms of these
(16:45):
agencies that are doing thisresearch for the industry.
All I'm trying to do is be themessenger and distill this
information.
I didn't make up the chart, butwhen I ask the people who did
make the chart what it means, isit's a paradigm shift, guys.
We have to think a little bitdifferently here.
Cyaneric acid has a lot ofbenefits to it, but too much
(17:06):
cyaneric acid doesn't give youany more sunlight protection,
but it's all the detriments thatgo with overstabilization.
So that's what we want to avoid.
We want to avoid too much CYA.
We don't want to have none.
SPEAKER_01 (17:26):
And the Pool Guy Podcast Show is teamed up with
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description.
(17:49):
Yeah, so look the person thathas a pool with a cyaneric acid
of 100-150 parts per million,they're gonna have a harder
time, especially with thatchart.
It was only at 30 parts permillion on that chart.
So I can imagine at 150 partsper million, how slow is that
chlorine's effectiveness?
SPEAKER_02 (18:05):
Well, it that's a great question.
I don't know the answer.
I'm sure there's parts that cando it, and you can extrapolate.
If you look at the data um andthere's a lot of data available,
there's charts that show thekill time, or the it's called
CT, contact time.
And it goes up a lot.
I'm not sure if it'sexponentially, but for instance,
(18:27):
Cryptosporidium is a verychlorine-resistant bug that
commercial pools really have toworry about in case there's like
a diarrheal accident with achild.
That problem can shut down anentire swimming pool and they
have to be forced to drain.
So the CDC gets involved andthey look at the cyanuric acid,
(18:48):
and they came up with a uh, Idon't know if it's a regulation,
but basically a limit, apractical limit that if you have
more than 15 parts per million,15, 1.5 parts per million CYA,
you have to drain your pool downto below 15 parts before you can
effectively sanitize it becauseyou couldn't even measure the
(19:10):
contact time required.
So it goes, it goes through theroof the higher your CYA.
And it's not linear, it's it'sit's kind of parabolic.
It goes up really fast thehigher and higher you go.
So if you have a hundred see 150CYA or above, there's really
only one thing Arenda wouldrecommend you do, and that's
drain a portion of your pool, ifnot all of it, to get that that
(19:33):
number down because it's it'sgot total control over your pool
at that point.
SPEAKER_01 (19:37):
Yeah, it's interesting.
I really think that the CYA, umsome people call it a debate in
the industry, but there's reallynot much debate if you look at
the data.
The higher the CYA, the moreproblems you're gonna have with
everything.
And not only that, but you haveto have a higher free chlorine
level and with the highercyaneric acid level.
So um all those are huge factorsin this.
(19:57):
Um so someone listening to thispodcast, where can they go to
get more information about uhthe chart that you showed, um,
all this all the educational uhmaterial that Arenda makes?
SPEAKER_02 (20:09):
Certainly.
Uh you can access all of itthrough the Arenda app, which is
a free app.
It's available in the Play Storeand uh the Apple Store.
Um in the menu you can seearticles.
You can search C Y A and get toit.
That taps into our blog on ourwebsite.
If you prefer on a desktop, youcan just go to our website
(20:30):
orendatech.com,O-R-E-N-D-A-T-E-C-H dot com.
Tap on the blog, all theinformation is there.
Type C Y A in the search bar,you'll see all the cyaneric acid
uh articles about it.
We've got 10 or more, I think.
We have a lot of videos aboutCYA as well where we explain
this.
And again, this data does notcome from us, so we hyperlink
(20:52):
out to our sources so you cansee it for yourself.
Um but you know, the opinionsthat I've shared today have been
vetted because I've spoken tothe people who wrote the charts,
and I've I I understand whatthey're trying to say in the
charts because they can be kindof intimidating to look at
without any context.
So, what I explained to youtoday is accurate to the best of
(21:13):
our knowledge.
And if anything like thatchanges, I'll be sure to update
our blog or anything else.
Because you know, sometimes whenthere's something new like this,
you gotta take the time to slowdown and make sure that it is
accurate and everyone's sureabout it.
This is pretty settled, it seemslike.
SPEAKER_01 (21:32):
Yeah, I think so.
I I think you know the adjustedaquinity thing has been
something.
That it's pretty much settlednow, too.
And that was pretty new for awhile there, too.
And I think cyaneric acid issomething that as an industry,
um, it's like a double-edgedstore.
We do need it because we can'tbe at the account every day to
add chlorine to the pool, likeback in the 50s or 60s.
(21:54):
I don't know when pools werestarted, run out of time.
Um, but you also you have torealize that this is something
that will bind up the chlorinein the pool, and there's got to
be some kind of effect withthat.
It's not something that you canignore as a factor.
SPEAKER_02 (22:09):
Yeah, and again, you it's stabilizer itself is not
the problem.
Over stabilization is theproblem.
It's too much, right?
Because if you have a goodratio, you get sunlight
protection, chlorine is stillfast enough to do its job, you
know, it's all good.
And that this is neg this isdebatable.
You could make an argumenteither way.
(22:30):
Arenda's opinion, the optimallevel is around 30 parts per
million, 15 to 30.
Uh, you can go as high as youwant.
After 50, it gets really hard.
After above 50 parts per millionCYA, it's very hard to maintain
enough free chlorine to keepthat ratio optimal.
But I mean, you can you can doit.
(22:51):
If you want 100 parts, okay, butyou got to maintain 7.5 parts
per million free chlorine allweek.
Good luck.
That's that's a really highnumber of chlorine.
But back to what I was sayingearlier, to kind of pull this
together, there's two sides towater chemistry, right?
There's sanitization, keeping itclean, healthy, all that stuff,
chlorination, and then there'sbalance.
(23:13):
Cyanuric acid dramaticallyimpacts both.
There's only a few other factorsthat do.
For instance, pH impacts both,but with cyanuric acid, pH is
kind of almost negligible on thesanitization thing.
Uh without CYA, of course, it'svery important.
But what does calcium hardnesshave to do with sanitization?
unknown (23:34):
Right?
SPEAKER_02 (23:35):
What does TDS have to do with sanitization?
Not that much.
But cyanuric acid is profound onboth sides of water chemistry.
So we have to maintain levelsthat can be managed.
SPEAKER_01 (23:47):
Yeah.
Well, I appreciate that, Eric.
And I thank you for your time todiscuss this and to really
unpack it in the understandableway for the listeners.
And if you're looking for otherepisodes, of course, you can go
to my website, swinging forlearning.com, and you're gonna
see about eighteen hundredepisodes available.
Just click on the podcast iconand the banner.
And if you're interested in thecoaching program that I offer,
(24:08):
you can learn more atPoolGuyCoaching.com.
Thanks for listening to thispodcast.
Have your rest of your week andGod bless.
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