You can find chlorine test strips at hardware stores, pool supply stores, and online. [3] X Trustworthy Source Centers for Disease Control and Prevention Main public health institute for the US, run by the Dept. of Health and Human Services Go to source Always use test strips that can differentiate between free chlorine and combined chlorine. Free chlorine is the level of active chlorine that’s sanitizing your hot tub, while combined chlorine is all of the chlorine that’s been used up. You need to be able to test free chlorine separately (not just total chlorine) so you know your hot tub has a safe level of active sanitizer in it. [4] X Research source
DPD stands for N,N Diethyl-1,4 Phenylenediamine Sulfate, which is the reagent used in the test kit. You can purchase DPD test kits in pool supply stores and online. Remember to measure for free chlorine with your test kit, not just total chlorine.
Having a professional hot tub technician test your chlorine levels ensures that you’ll get an accurate reading. They’ll also be able to offer advice if your chlorine levels are too high or low.
If your hot tub’s free chlorine level is under 3 ppm, add more chlorine instead.
If the chlorine levels are still too high, try replacing one bucketful of water at a time, testing your hot tub water after each one. For particularly high levels, you may need to drain your hot tub completely and refill it with fresh water. If you do refill it, make sure you sanitize it with the right amount of chlorine.
You can find chlorine neutralizer at pool supply stores and online.
