When owning a spa, the need to ensure that its water is sanitary for use should be paramount. The type of water sanitizer used in a spa, for example, is very important. Fortunately certain types of chlorine forms, including even Clorox bleach and its sodium hypochlorite chlorine, can work well in a spa. When using something like Clorox for spa water sanitation, though, pay attention to how often it's used and how you're using it.
No difference exists between the chlorine in Clorox bleach and the chlorine used to sanitize swimming pools. Chlorine is actually just chlorine, no matter if it's in liquid, solid or gaseous forms. Because most bleaches, including Clorox, contain sodium hypochlorite chlorine, they can be effective water sanitizers when used in the proper amounts. Clorox bleach contains from 5 to 10 percent chlorine by volume, and you don't need a lot to keep something like a spa's water sanitized.
Using Clorox bleach in a spa requires understanding some things about bleach. For one, bleach is alkaline and will raise a spa's total alkalinity and pH if the water isn't maintained correctly. For spas where chlorine is used to sanitize water, total alkalinity (TA) should be between 80 and 120 parts per million (ppm). Also, Clorox-sanitized water in an outdoor spa must be chlorine stabilized, and cyanuric acid (CA) is used to keep chlorine levels at 20 to 30 ppm.
To figure out how much Clorox to add to a spa's water, you need to know how many gallons the spa holds. Once a spa's total water capacity is determined, only add about 8 drops of Clorox per gallon of water. In a 300-gallon spa, 2,400 drops of Clorox would be needed (8 x 300 = 2,400). The 2,400 drops of Clorox comes out to about 4 oz. at 600 drops per fluid oz. (2,400/600 = 4 fluid oz.).
The water chemistry in a spa is just as important as the chemistry in a swimming pool and can also be balanced the same way. Add only enough Clorox bleach to a spa to maintain a chlorine level of 1.5 to 3.0 ppm, which 8 drops per gallon will yield. After adding Clorox to your spa, test its pH level to ensure it's between 7.2 and 7.8. Stabilize outdoor spa chlorine levels with about 0.06 lbs. of CA per 300 gallons.
If a spa's pH exceeds 7.8, scaling on spa surfaces will result. You can lower a spa's pH by using muriatic acid (MA) according to instruction. Approximately a cap full of MA in 300 gallons of water will reduce pH to below 7.8 and eliminate issues with scaling. Use only nonscented regular or Ultra Clorox bleach, never the splashless variety. And always avoid splashing Clorox onto spa surfaces or on your skin or into your eyes.