POOL CHEMISTRY 101: How to Keep Your Water Balanced | Swim University

– How do you keep your water clean? How do you keep the green water away, the cloudy water away,
the scaling, the bacteria, all that (beep)? You do it with water
chemistry. That’s right. Well, part of the way, but water chemistry
plays an important role. Whether you’re new to pool ownership or you need a refresher, we have you covered. But, of course, if we tried to cover everything about pool
chemistry in one video it would be like a three hour movie and I’m not supplying
popcorn for everybody. Just crazy. And, movie theater prices… So, we’ve broken pool chemistry
up into smaller little bits and this bit is all about pH, alkalinity, and calcium hardness. Let’s dive in. (guitar music) All right, quick disclaimer, everyone has their own methods when it comes to pool chemistry, but at the end of the day, we all just wanna help ya
take care of your pool, and we all want your
pool to be crystal clear and fun to swim in. That’s it. The information in this video is based on my own, personal experience in the pool industry and all the research we’ve done here at And, if I missed anything, please leave a comment
below to let me know. So first, let’s talk about pH. What the (beep) is pH? I’m sorry. I’m sorry. So, pH is the measure of
how acidic or how basic your water is. It’s on a scale from 0 to 14, where seven is perfectly in the middle. So anything below seven, it means your water is very, very acidic, and anything above seven
means your water is basic. In the pool world, we wanna keep your pH between 7.4 and 7.6. Now, the reason we even talk about pH is that it plays such an important role when it comes to your sanitizer,
specifically chlorine. When your pH is at the perfect level between 7.4 and 7.6, chlorine does it’s best work. And, when you have really acid water, it can do a lot of damage to your pipes, and to your filter system
and to the pool itself, and, not to mention, when you
open your eyes underwater, which some people tend to do, it’s gonna burn like hell. When your water is basic or really dry, when you get outta the pool you’re gonna notice that
you dry up much faster, which may sound like a good thing, but it really isn’t because
it could do a lot of damage to your pool, it can do
damage to your filter system, and, of course, it’s not
gonna make the chlorine work effectively. So, we don’t want your pH to be below 7.4, and we really don’t
want it to be above 7.6. In our world, we want that to be right, smack dab in the middle at 7.5 pH. Next, let’s talk about alkalinity. Alkalinity is pH’s bodyguard. This is how I describe it because pH is really volatile. If it rains, if you jump in, if you put a beach ball in your pool, I mean, I’m being drastic here, but pH kinda bounces all over the place. And, alkalinity, by adding
alkalinity to your pool, it’s sort of the pH buffer. In fact, it is the pH buffer. It stops, or it takes the big hits so that your pH doesn’t go wonky all over the 0-14 scale. It kinda stays in the middle. The alkalinity takes the brunt of the hit. And so, with alkalinity, we recommend that you keep your readings between 100 and 150 parts
per million of alkalinity. So, alkalinity and pH go hand in hand. They work together. Usually, if you have low pH, it means you may have low alkalinity, and vice versa, if you have high pH, it could mean you have high alkalinity. And, when you add chemicals
to either increase or decrease the pH or the alkalinity, they’re gonna both move at the same time, because, again, they work together. Now, we’ve kinda discussed
pH and alkalinity. Those are the two biggest,
most important things when it comes to pool chemistry. If the pH and the
alkalinity are in balance, and they’re between their ideal ranges, then you are in a good spot. So, how do we get there? How do we get the pH and the
alkalinity to be balanced? I know a lot of people struggle with trying to keep their pool balanced. I know it can be tough, but
here’s what we’re gonna do, the first thing we’re gonna do is make sure you get your water checked. You could use a liquid test
kit, or some test strips, or you can bring it in
to your local pool store to get it checked for you. Whichever way you measure, or whichever way you test the pool, you wanna know where you
stand with your readings. You wanna make sure that your pH, or you wanna make sure
you know where your pH is and you wanna make sure you know where your
alkalinity currently is. All right, so let’s assume
that you get your water checked and the pH and the alkalinity are low. What I would do in this case, is I would add just alkalinity increaser or sodium bicarbonate
which is also baking soda. You add that to the water and you wanna use a chemical dosing chart. If you don’t know how much to add, don’t just add a bunch of baking soda or add a bunch of alkalinity
increaser into the water. You need to know how much
you need to increase by. And, if you wanna have
chemical dosing charts, you can go to or you can check out
our pool care handbook which has all of the dosing charts in it for all of the chemicals
we’re gonna talk about. So, now that you know how
much you need to increase by, and let’s say your alkalinity is sitting at about 50 parts per million and we wanna get it up to
about 125 parts per million, you wanna add 75 parts per million. And so, depending on how
many gallons your water is, which is something that’s incredibly important to know beforehand, based on how many gallons you have, you’ll know how many
pounds or how many ounces or whatever you need to know, in order to increase the
alkalinity in your pool. When you increase the
alkalinity to the correct range, which I recommend being
at 125 parts per million, it is going to bring the pH up with it and hopefully it’ll bring up
the pH in the correct range. What you’re gonna wanna do is, after you add alkalinity to your water, and the way you add
alkalinity to your water is simply by broadcasting
it into the water, sprinkling it in, making
sure your filter’s running so it mixes it in. And then, a couple hours later, you wanna check it to make
sure that your alkalinity’s in the correct range and hopefully your pH is in the correct range as well. Let’s say your pH is a little bit low after you add the alkalinity, you can add pH increaser
to just increase the pH. You could also use sodium
borate to increase pH, or, it’s also known as Borax. So, in this case, we
have the real big tune, which is you wanna tune up the alkalinity with alkalinity increaser
or sodium bicarbonate and then you want to fine tune the pH with a sodium borate or a pH increaser to get the alkalinity and the pH right in the right level. So, what if your pH and
alkalinity are too high? This is less common, but if
you have a concrete pool, you might experience this. And, there’s a host of other factors, but basically, you wanna
add an alkalinity decreaser or a pH decreaser. In this case, I would use
something like muriatic acid, which we have an entire video on, to lower the alkalinity or
you can use pH decreaser. When you add either of these things, they’re gonna bring both
of those ratings down, both the pH and the alkalinity. And again, once you add this, you wanna know how many
gallons your pool is, you wanna know how much
you need to decrease by, and when you add it to the
water, wait a few hours, get it rechecked and make
sure that you hit your levels. Again, pH and alkalinity
are the most crucial parts of pool chemistry. Keeping them balanced
means staying on top of it. It means getting your
water checked frequently. Making sure that the pH and alkalinity are always in range. And, yes, things are gonna effect it. We’re talking about an outdoor pool, here unless you have an indoor pool then you have less
chances of this happening, but an outdoor pool we have
rain, we have swimmers, we have the environment. All of these things are gonna cause your pH and alkalinity to
kinda increase and decrease, as well as adding other pool
chemicals, like chlorine. So, just make sure that
the pH and alkalinity are always in balance and if you do that, that’s like 75% of all pool chemistry, is just keeping those things in check. All right, finally, I wanna
talk about calcium hardness. What is calcium hardness? It is the measurement of how
hard or soft your water is. And, it’s very similar
to pH in the sense that having very soft water can cause corrosion on your pool walls, in your filter system, and having very high
calcium can cause scaling to the inside of your pipes or your hoses or the pool itself and can
cause long term issues. So, it’s important to keep
the calcium hardness level at an ideal range between 175
and 225 parts per million. And, the good news about calcium hardness is it’s not as volatile
as pH and alkalinity. It’s not gonna change drastically with swimmers or with rain or
with environmental elements. Usually, you add calcium hardness at the beginning of the pool season and it will stay in your pool
for the rest of the season. Now, if you use calcium
hypochlorite shock, you are adding little bits
of calcium into your water all season long. But, if you’re not gonna use that shock, then just keep an eye on
the calcium hardness level. You may not see it go up
and down very drastically, but just make sure it’s in the 175 to 225 parts per million range. So, if you want more information on taking care of your swimming pool, specifically when it
comes to water chemistry, when it comes to pH,
alkalinity, calcium hardness, chlorine, all of that stuff, you can check out our pool
care handbook and video course which will teach you
everything you need to know about taking care of your pool,
especially water chemistry. Once you get it, once you buy this, it is constantly updated
and you have it for life. And, because you’re watching this video, and thank you so much
for watching this video, you’re gonna get a discount of 10% off by using the promo code VIDEO. Just go to to get your copy today. So, thank you so much, appreciate you watching this video. Again, if you have any
questions or comments or you think I missed
anything in this video, please leave a comment below, and if you want more information on pool and hot tub maintenance, go to and subscribe to our YouTube channel. Appreciate it. Thank you so much. And, as always, happy swimming. (guitar music)

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