Pool water. Spa water. Pretty much the same thing, right? Wrong! Spa water is a lot different than pool water and there are several reasons why.
Number one is the water temperature. A pool generally will be kept somewhere from the mid-70’s to mid-80’s (Fahrenheit) versus the spa typically being kept somewhere from 100 to 104 degrees Fahrenheit. These 20 to 30 degrees are huge in the chemical world. The warmer the water, the quicker the chlorine or bromine is used up/depleted. Chemical reactions just happen quicker at the higher temperatures. So, a spa just needs or uses sanitizer more quickly. Hot water also makes things like calcium a bigger challenge as calcium comes out of solution at higher temperatures. Finally, the warmer the water the more body oils and perspiration will be released by the users into the water. I know, it sounds gross, but do you really think you don’t sweat when you are in a spa or for that matter swimming in a pool?
The other reason why a spa water is different than pool water is the simple fact that you are talking way different gallonages. While a pool might need pounds or gallons of chemicals when being balanced or chlorinated, a spa requires teaspoons, tablespoons and ounces to treat. And here is an example of the volume difference in real life. Let’s say you have a 500-gallon spa, which would be a big spa by the way, and you have 5 people in the spa. That is one person per 100 gallons of water. Now let’s say you have a 16’ x 31’ inground pool with a volume of 20,000 gallons. The same ratio of 1-person per 100 gallons would equate to 200 people in your pool. Now that is quite the pool party. I think I will just sit in one of your chaise lounges and drink a beverage if you don’t mind.
So hopefully you can see that while pool water and spa water have similarities, they do require a little different treatment to keep them both clean, clear and safe for the users.