Pools and hot tubs need a lot of different chemicals to keep them at their best, for splashy fun all summer long. It can be a little bit confusing. I asked a friend with a pool about all of the chemicals he uses, and he explained them to me.
It’s hard to cite a friend as easily as an online article, but here is some of his information. Anyway, let’s look at the different types of things that need to be balanced in your pool to keep it up well: chlorine content, PH balance, and water hardness.
Chlorine is the most well-known and important component of your pool’s health. Chlorine keeps algae, bacteria, and fungi from growing in what should be clean swimming water.
Chlorine is somewhat confusing, because it isn’t just an issue about balance. You also need to “shock” your pool regularly. Some sources suggest you should shock your pool every two weeks; others say it should be done after a rainfall or after a large group of people has been in your pool.
Shocking is done by putting large amounts of extra chlorine in your pool. This kills any bacteria that have survived the usual low dose of chlorine. Chlorine also evaporates quickly, especially in sunlight, so shocking the pool regularly helps boost the amount of chlorine.
Again, chlorine evaporates faster in sunlight, so you should shock your pool at night. When you’ve finished, run the pump overnight to circulate the extra chlorine. Don’t swim for at least 8 hours after you’ve shocked the pool; the chlorine will be at unsafe levels.
You can use chemicals other than plain chlorine. Lithium hypochlorite and calcium hypochlorite are both chemicals with large amounts of chlorine, which dissolves out into the water when they are placed in the pool.
Saltwater pools are another option (https://www.bobvila.com/articles/saltwater-pool/); they use ordinary salt, with an electrolytic machine in the water that slowly transforms the salt into chlorine. This renews the supply of chlorine more easily, and without the irritant effects and sharp smell of ordinary chlorine pools. The installation and servicing are usually more expensive, but the day-to-day maintenance is much lower—just fill it up at the start of summer, check it occasionally, and relax!
If you don’t remember much from your high school chemistry class, discussions of PH might be confusing to you. Here’s a quick refresher.
The scale of PH goes from 1 to 14. 1 is a very strong acid; 14 is a very strong base. Both extremes are highly dangerous and corrosive. 7 is “neutral,” and it’s the PH level of pure water.
The range of safety is fairly wide. Baking soda, a mild base, has a PH of 8; soap is usually between 9 and 10. Lemon juice, a fairly strong acid, has a PH of 3. Just remember that how strong of an acid or a base something is doesn’t depend on how high the number is, but instead, how far away the number is from 7. PHs of 3 and 11 are equally strong.
The ideal PH range for a swimming pool is 7 to 7.6, a very narrow range that trends slightly towards the base end of the scale. This is why people often use baking soda in their pools; that increases the PH somewhat. Higher numbers, more basic, can cause mild skin irritation; lower numbers, more acidic, make swimmers’ eyes sting.
If your PH is too high, you can add small amounts of muriatic acid, a dried compound that dissolves in pool water. If your PH is too low, you can just add baking soda, as previously mentioned. Both are easy to find and common for a variety of uses, especially pools.
You probably have a good idea of the difference between hard and soft water already. You’ve seen crusty mineral deposits on faucets because the water was so hard it was leaving minerals behind; you’ve felt how strange water tastes when it’s extremely soft.
Water softeners can help if your water is too hard. Mineral supplements can help when it’s too soft. Like everything else, it’s a matter of balance.
Where to Get What You Need
The sheer number of pool chemicals are confusing. When you got your pool, the salesman may have recommended a set to you, but you can also find them all at once from larger stores. It can also be confusing to open your pool for the first time, since all the balances are a little different when you start, but places like Watson’s opening pool chemicals are a good way to start.
You may be able to get everything you need in one place from stores like that. Even if you can’t, I hope this article helped clear up some confusion.