The Low pH Danger Zone: Bob Lowry Breaks It Down

Episode Transcript
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SPEAKER_00 (01:51):
Hey, welcome to the Pool Vay Podcast Show.
It is Bester Bob Lowry.
I'm going to talk to Bob Lowryabout low pH and the dangers of
having really low pH in yourpool.
And of course, Bob Lowry was thepremier chemical expert in the
pool industry, and he has awealth of knowledge to share
with listeners, even after, ofcourse, his passing a few years

(02:13):
ago.
These recordings I think are agreat asset to the pool
industry.
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(02:33):
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Let's talk about something thatwe don't hear much about, but
recently I had a member of mygroup, he had a vinyl pool that
had a pH of six, which probablywould be lower than that in a
lot of cases, depending on thetest kitty was using.
And low pH typically is not aproblem you hear about.

(02:55):
High pH is something that wehear about a lot more, but low
pH can be a big problem also.
What happens if the pH gets toolow in a pool for a long period
of time?

SPEAKER_01 (03:08):
Well, when the pH is low, um the water gets to be
what we say is corrosive oraggressive.
And it can in a in a plasterpool, it can dissolve or start
to etch the plaster.
And so you get the plasterinstead of being real nice and
smooth, becomes kind of rough.

(03:30):
So we get etched plaster, we getcorrosion of equipment.
So the metallic parts that arein the any of the components in
the system, whether it's theheater header or the impeller on
the pump or whatever, whateveris in metal in the pool can
start to dissolve also.

(03:50):
And then the dissolved metalgets into the water and it is
invisible until it gets to acertain level.
And that certain level is whatwe call the saturation point.
When it reaches the saturationpoint for those conditions, then
the water can't hold anymore,even though more is dissolving.

(04:11):
When it does that, then itstarts to precipitate the metals
and we start getting staining.
Usually, when we get staining,it's because we've dissolved
some of the metal components inthe pool.
The other reason, of course, isif you're getting metal in the
incoming water.
And copper and iron are bothallowed to be in drinking water.

(04:33):
They're allowed to be at a lowlevel.
So when you add water to thepool, when it dilutes and
everything, you know, it's notsuch a big problem.
But eventually you can buildmetals up to the point where
they can stain the pool.
So it is something that once ina while, as a service tech, uh
maybe every couple of months,you should run a test for iron

(04:55):
and copper and see if thelevel's gone up.

SPEAKER_00 (04:58):
And I don't want to plug too many products, but I
have the new color Q Pro 9 2X or2X Pro 9.
And I really like the fact thatthat photometer tests for copper
and iron.
I think if you're a poolprofessional, you should have
some way of testing for copperand iron in the water as part of
your regiment.

SPEAKER_01 (05:16):
Absolutely.
You you know, I and I often tellguys, listen, you know, you're
gonna tell me you don't want tospend six or seven hundred
dollars on a test system, butyou just spend$40,000 or$50,000
on the truck that you drivearound in to take care of the
pools, you know, and and how doyou justify that when you can't

(05:36):
spend$500 on a test custom testsystem?
So uh get a good test system.
You test the water every timeyou go to every pool.
If you're getting bad resultsand adding chemicals based on
those bad results, are isn'tthat test kit affecting your
life, your livelihood, yourreputation, and and you're

(05:59):
letting it fall on a on a cheappiece of junk test kit?
You know, get a good one, getsome good answers so you can add
the right chemicals to the pooland do your job right.

SPEAKER_00 (06:09):
Yeah, exactly.
And so back to the low pH hereon a vinyl and fiberglass pool,
why is it that the pH seems toalways drift lower on those
surface types?
And I know that a lot offiberglass manufacturers will
avoid the warranty on you if youuse tablets, three-inch triclare
tablets, because I think becausethose lower the pH, of course.
And so why with that poolsurface type are we all running

(06:32):
into lower pH?

SPEAKER_01 (06:34):
The vinyl, I guess we should back up.
On a plaster pool, we've gotsome alkalinity and some calcium
coming out of the pool itselfand dissolving into the water.
It's just a little bit, but it'senough to be uh to keep the
water in balance.
But what happens is with a vinylpool, there isn't any source.

(06:58):
And so once the pH andalkalinity get a little bit low,
the water becomes aggressive andit's looking for something to
dissolve.
And if there's any metal thatstarts dissolving it, if if if
um interestingly enough, low pHactually affects the vinyl more
than chlorine level does.

(07:19):
When I was at when I was atLeslie's as their technical
director, one of the things Idid was I took pieces of vinyl
and I literally poured liquidchlorine on top of vinyl fresh
out of the jug onto the vinyland it didn't do anything.
On the other piece of vinyl, Iput one drop of murianic acid

(07:43):
and the color disappeared out ofthe vinyl.
One drop and it disappeared tothe color.
It made a it made a white spoton blue vinyl where where one
drop hit it.
So um low pH is no good forvinyl.
But it goes low because there'snot a source of alkalinity and

(08:05):
calcium that's coming out of thewalls.

SPEAKER_00 (08:08):
Is that true also for hot tubs?
The above-ground fiberglass hottubs.
I'm always running into thosewith low pH also.
Or is that the bather load?
What can be causing that in likea 350-gallon above-ground hot
tub?

SPEAKER_01 (08:24):
Well, that can be uh that can be the chlorine source.
If you if it's a busy, if it's abusy spa, uh you've got either
trichlor or dichlor being put inthere, both of which are a
little bit acidic.
Um, a lot of times we see spas,the pH going very high all the
time because we've got aerationand turbulence, which raises the

(08:48):
pH a lot.
It may be that if you've got aspa like that, it may not be
used very much, and then or itmay be used a lot, and they're
putting a lot of chlorine inthere, and the the chlorine
level is actually lowering thethe uh the pH and the
alkalinity.
And don't forget, um our bodieshave a pH of about 7.45, believe

(09:12):
it or not.
Overall, blood system,everything, 7.45.
So keeping the pH eitherdirection 0.3, plus or minus
from that is is okay.
But when you get outside of thatrange, it can become irritating.
So we're looking at 7.8 or 7.2being a problem.

(09:37):
So when you get to 7.2 or whenyou get to 7.8, you can have
body irritation.

SPEAKER_00 (09:44):
On both ends of the spectrum.

SPEAKER_01 (09:46):
That's right.
Um, and you combine that with alittle bit of combined chlorine
or chloramines, and chloramines,believe it or not, are are
irritants, and you can smellthem at 0.2 parts per million,
which is the reason that we saythat combined chlorine should

(10:06):
not be greater than 0.2 partsper million, because it becomes
an irritant at that level, andyou can also smell it.

SPEAKER_00 (10:13):
And so the best way to raise low pH.
Now, I'll throw this out there.
I've done this, and a lot of themembers of my group, they'll go
to Walmart and they'll buy 20mule team borax and they'll put
it into the raise the pH of thepool.
And you're adding borease to thepool at the same time at some
level, but what's the best wayto raise the pH?
I think the borax product, in myopinion, is a great way to do it

(10:35):
if it's really low and you'rewanting to raise the pH.
But you wouldn't be using bakingsoda.
That's a lot of people areselling that as something that
raises pH.
I know even on the bag of thebaking soda, you know, if you
buy the the 10-pound bag atCostco, it'll have a it says,
you know, the raised pH, addthis to the pool, but that's not
that's a misnomer, right?

SPEAKER_01 (10:56):
Yeah, it really is.
Um bicarb, so that you can get alittle bit of an understanding,
the strongest solution you couldmake of bicarb would have a pH
of 8.3.
So that's the highest it can go.
Even if you you put a whole bagof of bicarb in your spa, the pH

(11:17):
isn't gonna go over eight pointthree.
And you can see if your pH wasalready seven point two or seven
point four, if you added somebicarb to the water, it's really
not gonna change the pH verymuch.
You know, because it's not verystrong.
You know, soda ash has a pH of13.

(11:39):
So when you add it, there's abig difference between 7.5 and
13.
So it raised the pH a lot.
But bicarb does not raise the pHunless the pH is very low.
If the pH was say 6.8 and andyou put in some bicarb, it's

(11:59):
gonna raise the pH, but not notvery much.
If you if you added enough toget the alkalinity to the right
spot, the pH would still be low.
So um so you can't use bicarb toraise the pH.
If you ever get the pH below uhabout five, you can't put bicarb

(12:23):
in anyway.
It won't it won't raise the pHat all.
Because below a pH of five, whenyou put bicarb in, it gases off
as CO2.
And so um so it doesn't work.
In any case, I would not usebicarb to raise pH at all.

(12:45):
Um you can use borax, it adds alittle bit to alkalinity.
Borax has a pH of about 9.2.

(13:15):
So when you add it, it's itraises the pH more than bicarb
would, but less than what sodamight.
Um and it doesn't appear toaffect your alkalinity much, but
as you might have guessed, youknow, we make a an adjustment to

(13:37):
the saturation index forcyanuric acid.
There is also an adjustment youhave to make to uh the
saturation index for borate.
If you do put borates in yourpool, your alkalinity figure is
uh your total alkalinity readingis actually lower than than you

(13:59):
think it is.

SPEAKER_00 (14:00):
Percentage uh number for that, like offhand?

SPEAKER_01 (14:03):
Um no, it doesn't work that way.
It does for cyanuric acid.
We can use basically one-third,but because it's a buffer to
keep the pH from going high, thehigher the pH, the more it
affects it.
At a pH of 7.5, the if 50 partsper million of borate would only
affect the reading by about sixor seven parts per million.

(14:26):
But as you get up to seven,eight, or eight, now it affects
at about twenty.
And if you get up above eightpoint two, it affects at about
forty.

SPEAKER_00 (14:35):
And we should also mention that soda ash also
raises alkalinity as well as pH.

SPEAKER_01 (14:41):
Yes, and it raises it to ounce per ounce, it raises
it more than uh bicarb does.

SPEAKER_00 (14:48):
So if you have a pool with low alkalinity and low
pH, the so soda ash is perfect.

SPEAKER_01 (14:54):
That's right.
That's right.
When when you need to raiseboth, use soda ash, and when you
need to to just raisealkalinity, uh use bicarb.
But don't forget that you canaerate to raise pH.
Yeah.
And so a lot of times I tellpeople, listen, if you're if
your if your pH is low and youralkalinity is low, you can add

(15:18):
just bicarb to get to the exactalkalinity that you want.
And then aerate till you get topH of seven, five, and you'll
have a perfectly balanced pool.

SPEAKER_00 (15:29):
Yeah.
So if you have a hot tub thathas a really low pH, let's say
it's at six, and alkalinity isat 40, put some baking soda in
there and then turn that thingon and let it run for a couple
hours.
That's right.
That's right.

SPEAKER_01 (15:39):
Put enough baking soda to get the alkalinity up to
80 or 90, and then and then turnthe turn the aerator on, uh, you
know, the blower and the and thejets and whatever.
And in a spa, uh, you'llprobably raise the pH up to 7.5
in about a half an hour.

SPEAKER_00 (15:59):
Yeah.

SPEAKER_01 (16:00):
It's really a short time.

SPEAKER_00 (16:02):
And then I guess lastly, the lower the pH, I
mean, I know the cyaneric acidis a big factor in the chlorine
kill factor, but you mentionedthat at the lower pH, it makes
the chlorine, the killing partof chlorine more effective.
So a pool at 7.6, technically,let's say the cyaneric acid
level is in range at 50 parts amillion, pool at 7.6 or 7.4, the

(16:25):
chlorine will have a betterkilling ability than a pool at
8.0.

SPEAKER_01 (16:30):
You know, probably not, because we used to we used
to believe that all of thechlorine was, you know, subject
to that that fraction that Itold you, 50% HOCL and 50% uh
OCL minus.
But the problem is that when 97%of the chlorine is bound to

(16:54):
bound to cyanuric acid, andyou've only got three percent,
it changes things a little bitbecause the concentration of
cyanuric acid and theconcentration of chlorine
changes that 3% figure.
It it almost doesn't matter asfar as it being effective.

(17:14):
The real important thing is tois to get the proper level of
chlorine in there.
So it doesn't necessarily affectthe killing power of 7.5 versus
7.8.
The killing power is not goingto be that much different, but
you need to have enough chlorinein there to prevent the algae.

(17:36):
And again, it goes back to thatpercentage rather than doing
what the pool stores say andkeeping two to four parts per
million of chlorine in thewater, it doesn't always work.
You know, two it is two to four,but you're gonna find in most
cases that the minimum levelneeds to be nearer to four than

(17:56):
it does two.

SPEAKER_00 (17:58):
And so the guys that are obsessed about keeping the
pH at 7.4, 7.6, they're prettymuch it's not making a big
difference.
You know, I think in the old olddays we're always taught that a
high pH makes the chlorine lesseffective, but that's the old
Yes, and we believe that becauseas the as the pH goes up, the
effectiveness of the chlorinegoes down.

SPEAKER_01 (18:20):
Um so at a pH of of 7.8 or or 8.0, you've only got
about 20% of the chlorine in thekilling form and 80% in the
non-killing form.
That doesn't matter so muchbecause of the influence of
cyanuric acid and theconcentration of chlorine and
cyanuric acid.

(18:41):
So um it it doesn't matter thatmuch anymore.
But we still need to balance thepool.
It's not to say that you cankeep a pH up around eight and
and still have have good killingpower and everything.
You will, but you're gonna havebathers unhappy because we got
above that 7.8 level where itstarts to irritate bodies.

(19:05):
So, you know, you don't want torun a pool at 7.8 because you're
only you're right on theborderline of where the water
now becomes bathers will noticethe pH.
Either they get they get itchyskin, they get irritated eyes,
or something like that, becausethe pH is is 7.8 and all it

(19:25):
needs to go is to 7.9, and nowyou irritate the bathers.
You know, at 7.5, you've got 0.3before you can have a problem.

SPEAKER_00 (19:34):
If you're looking for other podcasts, of course
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banner, click on the podcasticon.
There'll be a drop down menuover eighteen hundred podcasts
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And if you're interested in thecoaching program that I offer,
you can learn more at poorcoaching.com.
Thanks for listening to thispodcast.
Take a rest of your week and Godbless.

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The Low pH Danger Zone: Bob Lowry Breaks It Down

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