When Your Saltwater Pool Takes a Winter Nap

Cold water doesn’t just chill your pool—it changes how your salt system works. We break down what really happens when temperatures drop, why most cells throttle or shut off around 50 to 60 degrees, and how to keep water clear without burning through gear or cash. If you’ve ever wondered whether to pull the cell, which sanitizer to lean on, or how to set yourself up for an easy spring, this walkthrough gives you a step-by-step plan.

We start with freeze protection and the simple move that prevents expensive damage: remove the cell and install a dummy cell when hard freezes or power outages are possible. From there, we map out a winter sanitizing strategy built around trichlor tablets in a floater—not the skimmer—to deliver slow, steady chlorine while topping up cyanuric acid. You’ll hear practical tablet dosing for 15,000 to 20,000 gallon pools, why cold water slows dissolution, and how a modest tablet plan can place your CYA near the 70 to 80 ppm sweet spot for salt systems once the sun returns.

When storms zero out your chlorine, we explain why liquid chlorine is the best fast-acting boost for salt pools in winter. Its byproduct is sodium, so you avoid adding calcium that can scale up your cell plates. 

• freeze risk to salt cells and dummy cell use
• why cold water reduces electrolysis and output
• heated pool exception to winter shutdown
• trichlor tablets as winter sanitizer backbone
• avoid skimmer placement and use a floater
• tablet dosing by pool size in cold water
• winter CYA top-up strategy to target 80 ppm
• liquid chlorine boosts without calcium byproduct
• verify salinity with a digital meter in spring
• switch off tablets and reactivate the generator

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Episode Transcript

SPEAKER_00 (01:02):
Hey, welcome to the Pool Guy Podcast Show.
In this episode, I'm going totalk to you about the winter
months when the pool water isgetting colder and your
saltwater system.
There are some notable things toknow about a salt water system
in the colder winter months,especially when you leave the
pools open all year round, orthose areas where you leave the

(01:23):
pools open all year round, Ishould say.
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(01:45):
I'll caution you that if you arein these areas where you can get
freezing temperatures and you doleave the pool open, there's
parts of Texas, there's beendeep freezes that have hit areas
where the power has gone out andit's been you know freezing
temperatures.
And one thing that you wouldwant to do to prevent damage of
the salt cell during the wintertime is to remove the salt cell

(02:09):
and put a dummy cell in itsplace.
They do sell various dummy cellsfor the pent there and hayward
systems.
You can purchase those.
If it does freeze, what happensis that the water will expand

(02:32):
inside there and it'll crack thesalt cell and pretty much
destroy it and ruin it.
So if you see pictures of a deepfreeze in Texas from a few years
ago, you'll see a lot of saltcells that exploded basically
from freezing, the waterfreezing, crystallizing, and
then expanding when it defrostedand cracking the plastic.
They're usually pretty robust,but under those circumstances,

(02:53):
the salt cell is not going towork.
And of course, if you close yourpool down in the wintertime, you
want to remove your salt cell.
That's part of the closingprocedure.
But in those areas likeCalifornia, Nevada, Arizona,
Florida, parts of Texas whereyou don't close your pool, leave
them open all year round, thereis something to note about the
salt system is that it useselectrolysis to turn the salt,

(03:16):
sodium chloride into chlorine,and as the water temperature
drops, it slows downdramatically.
Electricity does not conductreally well in cold water, and
so you're gonna see asignificant drop-off of
production.
Even the cells will shut down, alot of them will have a cold
light indicator or cold water ordisplay water temperature too

(03:40):
low, and usually around 50 or 60degrees is when the salt cells
will shut down because of thecold water, and it's just not
able to really do its process tokeep it simple in cold water.
Now, there are some good thingsabout the cold water, of course,

(04:01):
is that you know algae andbacteria grow slower in cold
water very slowly.
In fact, it may not it may seemlike algae doesn't grow in cold
water at all, but it is growingslowly in some cases.
So it's one of those thingswhere it's not a deal breaker, I
should say, to have a salt watersystem because in the cold

(04:22):
months it shuts down.
In fact, no one's using the poolin the cold months, so it's
actually better that it shutsdown and you're kind of saving
the life of the salt cell by notusing it, you know, 365 days out
of the year.
Now, of course, if you heat yourpool in the winter to 70 or 80
degrees, well, I guess you wouldprobably heat it to 80 degrees
in the winter.

(04:42):
70 is probably still cold formost people.
Now I had a customer that hewas, you know, one of these
workout buffs, and he reallyliked staying in shape, and he
would heat his pool in thewintertime to about 85 degrees,
and his gas bill he said wasabout twelve or fourteen hundred
dollars a month, and he didn'tcare.
He was like, I'm just gonna usemy pool all year round.

(05:05):
So in that situation, of course,the salt system is not gonna
shut down because the watertemperature is being
artificially elevated by theheater, and it's just basically
like summertime for the saltsystem, it won't know the
difference.
But in cold water, there is abig marked difference.
Most systems will know that thewater temperature is cold.
There's a there's a temp sensorin there for the water

(05:26):
temperature, and if it getsbelow a certain temperature,
it'll shut the system down, oryou'll it'll produce very low,
very low amount of chlorinebecause of the fact that it just
can't produce in the wintertime.
So you have to switch over to adifferent sanitizer in the

(05:47):
winter time.
In my opinion, the best chlorinetype to use in the wintertime in
a salt water pool are trichlortablets.
And I'll give you a few reasonswhy I primarily use trichlor
tablets and salt pools in thewintertime.
So you'll have to have a floaterbecause most pools with a salt
system, some of them have achlorinator built in and some

(06:11):
don't, but most of them will nothave an inline chlorinator, so
you'll have to get a floater.
This is very important that youdon't just put the tablets in
their skimmer.
Now, there's a lot of reasonswhy you don't want to put
tablets in the skimmer, butbriefly I'll just say that
trichlor tablets are veryacidic, they have a pH of about
2, 2.7.
And if you put them in theskimmer basket, if you're

(06:32):
running in the pool 24 hours aday, just really no worry about
it because the water is flowingthrough.
But if when you turn the pooloff, all the acidic water sits
in the skimmer, and then for 10hours or 12 hours and the pool's
off, it's just sitting andbuilding up.
You turn on the system, and allthat acidic water goes right
through the system, and thatcould cause staining out of the

(06:53):
return line, staining in themain drain of the pool, and it
could damage the equipment.
So you definitely want to have afloater for the trichlor tablet
in the winter time.
Here's why I suggest trichlortablets in the winter because
half of the makeup or half ofthe ingredients of the trichlor
tablets is cyaneric acid, andfor the summertime you want to

(07:16):
keep your salt water poolcyaneric acid at about 80 parts
per million.
And the way to do this, ofcourse, is to add cyaneric acid
to the pool directly eitherusing liquid pool conditioner or
the granular or the powderedcyaneric acid, and you'd have to
buy the product and add itbecause the salt system does not

(07:37):
have any stabilizer built in.
There's no cyaneric acid beingproduced by the salt water
system, and the only way to addit is manually at the beginning
of the season.
And as the pool, of course,evaporates, the water
evaporates, and you get somerain in your area, the cyaneric
acid level drops down withnothing replenishing it because

(07:57):
the trichlor tablets, like Imentioned, are about half by
weight cyaneric acid.
So if you're using trichlor,you're adding cyaneric acid to
the pool.
But if you're not using trichlortablets and you have a salt
water system, you're not addingany cyanaric acid.
I think you're following mehere.
So in winter time, since thepool water is pretty cold
anyway, the tablets are going todissolve very slowly in the

(08:21):
floater.
But as they dissolve in thewintertime, and you don't need
too many tablets, I shouldemphasize this.
If you have, I'm just gonna giveyou some kind of ballpark sizes
of pools and how many tablets Iusually use in the wintertime.
If you have a 20,000 gallonpool, one tablet in the floater,
pretty much closed off all theway, is sufficient in you know

(08:43):
50 or 60 degree watertemperature to sanitize that
pool.
If you have a 15,000 gallonpool, I would break that tablet
in half in some cases and put itin there.
You could put a whole tablet in,it's not gonna cause a problem,
in my opinion.
So one tablet per 15 to 20,000gallon pool is sufficient.
Smaller pools, you may want tobreak the tablets in half and

(09:05):
you know, use half a tablet inthere because there's really not
a big chlorine demand in coldwater.
The nice thing about thetrichlor tablets, then you if
you're using, you know, maybeone tablet every two or three
weeks in the pool, maybe onetablet a month in some cases,
depending on how cold the wateris or how small the pool is,
you're adding cyaneric acid tothe pool, but you're adding very

(09:27):
small amounts of cyaneric acid.
So here from November throughabout April, beginning of April,
when the water starts heating upenough to where the salt system
reactivates, you may use five orsix tablets, let's say
basically.
I'm gonna just say you're gonnause, I'll just keep it simple
and say you're gonna use tentablets.
How's that?

(09:47):
That way we can do the math mucheasier.
Let's say again, 10 tablets,eight ounces per tablet.
In the wintertime, that's about80 ounces of total chlorine
tablets.
About half of that is cyanericacid, maybe 48% to be more
accurate.
So if you're using 10 8 ouncetrichlor tablets, you're adding
about 2.4 pounds of cyanericacid to the pool in a winter

(10:10):
time.
That's a kind of a boost foryour pool in the summer, so that
when you go to add the cyanericacid or conditioner or
stabilizer to the pool, howeveryou want to phrase it, you
already have some that you'readding to the pool in the

(10:45):
wintertime.
Even if you double that, you'reusing 20 tablets in the winter
time, that's going to add aboutfive pounds of cyaneric acid to
the pool.
And that might just be enoughcyaneric acid for the whole
season for your salt watergenerator, depending on your
pool size.
You have to kind of do the mathand the calculator based on your
pool size.
So you're not adding a ton ofcyaneric acid in the wintertime

(11:05):
to the pool, and you're kind ofrecharging the cyaneric acid
that you lose during the regularcourse of the season for the
salt water generator, if thatmakes sense.
So that's the benefit of thetrichlor tablets, of course, is
that you're adding some cyanericacid in the wintertime, which
will come in handy andbeneficial in the summertime.
Because a saltwater pool doesneed cyaneric acid in there to

(11:28):
protect it from being destroyedby the sun's UV rays.
Now, when they first came out,I'll just go back and share this
story.
When the salt water systemsfirst came out, I was doing pool
service, of course, when theyfirst hit the market.
Penthare was one that startedmaking a lot of them with the IC
IC systems and tetochloresystems.
And the Penta rep was like,yeah, this is great.

(11:50):
This is a great way to sanitizethe pool.
And you don't need to addcyaneric acid to it because it's
going to be producing chlorineall the time for you.
And it's something great.
That was one of their salespitches.
And it turns out you do needcyaneric acid because, as Bob
Lowry says, one reason why youneed it is because all that
chlorine comes out of the returnjets.
Maybe you have two return jetsin the pool, and it's a highly

(12:12):
concentrated amount of chlorinecoming out of there, and the
sun's UV rays will destroy mostof that in that concentrated
area, unless you're protectingit with the cyaneric acid.
Now, the old school of 30 to 50parts a million does work
effectively in pools that areusing you know liquid chlorine
or calhypo.
But in a real world situation,since there's so much chlorine

(12:35):
coming out of the return jets insuch a concentrated area, you
need a higher level of cyanericacid to protect it, and that's
why 80 parts a million has kindof become the industry standard
as far as the cyaneric acidlevel in a saltwater pool.
So the tablets will help youachieve that in the wintertime,
and you may not have to add anycyanaric acid products to

(12:55):
cyaneric acid razors orproducts, you know, stabilizers
or powder or liquid stabilizerto the pool at that point in the
winter time.
Now, one other chlorine typethat you can use in the
wintertime, let's say you'reusing tablets and you have a
pretty major rainstorm and thechlorine level zeroes out in the

(13:16):
pool, which does happen becausethe trichlor tablets in the
winter time, I did mention thatthey dissolve very slowly in the
floater.
They're not going to give you alarge dose of chlorine because
of the cold water and the factthat they don't dissolve rapidly
in the cold water.
So there are occasions where thechlorine level is going to drop
down because of a rainstorm, ormaybe you didn't put enough

(13:37):
trichlor tablets in there andthey were dissolving too slowly.
So let's say you check thechlorine level and it's at one
part per million.
Well, the best chlorine type touse to raise the chlorine in the
pool, in my opinion, would beliquid chlorine.
Why liquid chlorine overcalhypo?
Because liquid chlorine has abyproduct.

(13:57):
They all have byproducts.
Trichlor has cyanuric acid,calhypo has calcium.
Well, the byproduct of liquidchlorine is sodium.
So you're adding some salt tothe pool.
Now, as you know, in the wintertime, you know, you get some
dilution, and then in thesummertime you have to add bags
of salt to the pool to bring upthe salt level in the pool.

(14:19):
Well, if you're using liquidchlorine as another sanitizer in
the winter, along with trichlortablets, you're adding cyanuric
acid with the trichlor, and thenyou're adding some sodium to the
pool, not a huge amount, butyou're adding some sodium to the
water, and that is the mostcompatible chlorine type to salt
for a salt water generator.

(14:41):
Because if you're adding calciumto the pool, you may cause the
salt plates to get some calciumbuildup with calhypo.
So adding liquid chlorine iskind of like a a substitute to
the salt water system that'svery, very similar, and the
byproduct again is sodium.
So liquid chlorine is a greatway to raise the chlorine level

(15:02):
in the pool in the wintertimewith a saltwater system when you
need to.
If the trichlor tablets are notsufficient to raise the chlorine
level up and keep and maintainthe chlorine level, I should
say, month in, week in and weekout while you're not using the
salt water generator.
Now, coming out of winter, hereApril and May is when we start
firing up the salt water systemsagain.

(15:24):
And one mistake that is oftenmade is to trust the salinity
reading on the system itself.
Now the water is still fairlycold.
The cell might even be dirtyfrom you know if you didn't take
it out and put a dummy cell in.
And so I wouldn't trust thesalinity reading of the system.
Hayward is notorious for this,giving you really low salt
readings when it's really notlow.

(15:45):
Some Pentair systems will dothis as well.
So I would say when you'restarting up the system again in
April or May here in California,get a digital salinity meter,
buy one on Amazon.
You know, I like the Hawk brand,I like the Lamotte brand ones.
These are great salt watersalinity testers.
Get one of these and test thesalinity level.

(16:05):
A lot of these will compensatefor temperature, and then you're
going to get a true salinityreading.
You don't want to overdose thepool with salt at the beginning
of the season because thenyou're going to drain some water
out, or you may have too muchsalt when the system really
fires up and is running at youknow with the water temperature
at the correct level.
So make sure you check thesalinity level with an

(16:26):
independent digital salinitysalt reader, and then you can
add salt accordingly once youget the accurate reading.
And again, everywhere it'sdifferent when the system
comebacks come back, when thesalt systems come back online, I
should say.
And here in California, Apriland May are the months when the
water temperature gets into the70s, and the salt water systems

(16:48):
are able to reactivate and makechlorine for the pool.
But then you just take out thefloater, stop using the trichlor
tablets, and then the saltsystem will generate the
chlorine during those spring andsummer months for you and into
the fall.
And into the winter months hereagain, from usually late October
into the beginning of March,you're using an alternate

(17:10):
chlorine type because the saltwater generators are just not
producing chlorine during thattime.
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Thanks for listening to thispodcast.

(17:31):
Have you guys your week and Godbless.