Pool School

Matt Giovanisci: 00:00

Everyone. And welcome to Pool School by Swim University, where we help you keep your pool clean and clear all year. My name is Matt, and I'm the founder of swimuniversity.com. And on this episode, we're talking about how much shock you need to add to your pool. Let's dive in.

Matt Giovanisci: 00:28

Real quick. If you want more help taking care of your pool, be sure to grab our free pool care cheat sheet at swimu.com/cheat. Are you wondering how much shock you need to add to your pool? Well, the exact amount of shock you need depends on the size of your pool, the type of shock that you're using, and whether or not you've got an algae problem. In general, you're gonna wanna add 1 pound of chlorine shock for every 10,000 gallons of water in your pool.

Matt Giovanisci: 00:52

But if you're experiencing issues like green water, then you'll need to add more. So first, what happens when you add shock to your water? Well, shock being a pool is the process of adding a highly a highly concentrated dose of chlorine to quickly raise the levels of free chlorine in your water. And that high concentration kills things like algae and bacteria and helps to break up what are called chloramines. And chloramines are what are what is also known as combined chlorine.

Matt Giovanisci: 01:22

Now combined chlorine happens when free chlorine in your water gets used up after combining with contaminants. And it's the combined chlorine, AKA chloramines, I know there's a lot of chlorine here, that causes that nasty chlorine like smell in your pool. That classic summer smell, which is not necessarily a good thing. Using a chlorine shock like calypo shock or dichlor shock once a week will help kill these contaminants and break up the chloramine buildup. You can also use a non chlorine shock to get rid of the chloramines in your pool, but it's not gonna kill the algae.

Matt Giovanisci: 02:01

So how much shock do you need to add? Well, a standard dose of shock is, like I said, 1 pound of shock per 10,000 gallons of water. But you wanna always double check the label before adding it to your pool. The goal is to quickly raise your free chlorine levels to at least 10 parts per million or 10 PPM or higher. This will increase your free chlorine and decrease your combined chlorine.

Matt Giovanisci: 02:27

Your free your free available chlorine levels normally should be between 1 3 parts per million with 3 parts per million being ideal. Your combined chlorine levels, aka chloramine, should be no more than 0.5 parts per million or as close to 0 as possible. Now, if your combined chlorine levels are a lot higher, like 3 parts per million, you're gonna wanna add a double dose of shock. Regular weekly shocking can help keep your free and compliant combined chlorine levels in the right place. Now you just be sure that you balance your pH and your alkalinity before shocking the water so that the shock can work more effectively.

Matt Giovanisci: 03:06

And always test your chlorine levels before and after shocking. And if you're gonna be using chlorine shock, make sure you do it at night. Because the chlorine shock that you add is unstabilized, and the sun will burn off 1 part per million every hour. And so if you do it at night, you will get the full 8 hours of that chlorine. But how much shock should you add to kill algae?

Matt Giovanisci: 03:31

Well, shocking your pool with a double, triple, or even quadruple dose of shock is the most effective treatment for algae. So if you have light green or teal green pool water, this is early stage algae growth. So you'll need to double shock your pool with 2 pounds of shock per 10,000 gallons. If you have a darker green water or significant algae growth, then you'll want to triple shock your pool with £3 of shock per 10,000 gallons. And finally, if you have black, green, or extreme algae growth, and you'll know, you'll need to quadruple shock your pool with £4 of shock per 10,000 gallons.

Matt Giovanisci: 04:14

And remember, only chlorine based shock will kill algae. A non chlorine shock can help refresh your free chlorine levels, but it's not gonna actively combat the algae problem. And algaecide won't work to kill significant algae issues either. It's more effective at preventing algae from happening in the first place. So can a pool be shocked too much?

Matt Giovanisci: 04:38

Yes. It can definitely it's definitely possible to add too much shock, especially if you have a smaller pool. It can take much longer for the chlorine levels to drop back down to a safer range if you have less water. So be sure to test your levels after shocking. And do not use the pool until the chlorine has dropped back down to a safer range of about 3 parts per million.

Matt Giovanisci: 05:00

Finally, can you use bleach or liquid chlorine to shock a pool? While, yes, technically, you can use liquid chlorine or bleach to shock your water, you'll have to use a lot more to do it. Remember, your goal is to quickly raise your free chlorine levels to 10 parts per million or higher. So regardless of what type of chlorine that you use, you wanna test the water beforehand and you and after, of course, after super concentrated, you know, after a super concentrated dose of chlorine. And the only thing I'll say about liquid chlorine and bleach and all those things, bleach is about 6% chlorine.

Matt Giovanisci: 05:41

Liquid chlorine is about 12% to 15% chlorine, and you need a lot of it. That's a lot of gallons, a lot of heavy material that you have to go to the store to buy, transport big, multiple gallons of bleach in your car, and you know you hit a you hit a pothole, what happens? Okay? And then you have to dump all of that in your pool. The reason why people like liquid chlorine is because it mixes into the water very quickly and it kills very fast.

Matt Giovanisci: 06:11

However, it's just a pain, especially when you have a really, really big pool. That's why we tend to to use the small 1 pound bags. They're super light. They're highly concentrated, and then you can just turn them into liquid chlorine by adding them to a bucket of water, pre dissolving it, and then adding it to your water. You get the same effect.

Matt Giovanisci: 06:29

Now remember, if you need more help with pool pool maintenance, grab our free pool care cheat sheet at swimu.com/cheat. And if you found this episode helpful, subscribe for more pool maintenance tips on your favorite podcasting app. And when you do, please leave us a review because your support will help more pool pool owners. I can't say pool today. It's gonna help more pool owners like you find the show.

Matt Giovanisci: 06:50

That's it. Thanks again, and happy swimming.