Free chlorine disappears quickly

[Paul van Dort]

Hi all,
I have a Hotspring Triumph since a year. I replaced the water 4 times since. A recurring problem is the fact that the free chlorine disappears quickly. When I add chlorine (via bleach) the reading via test strips indicates 10PPm. after 1=2 hour it is dropped to 0, while the spa covered and not in use. (we prefer to use it while open ) PH, alkaline and Stabilizer (CYA) are kept perfect referring to the the test strips.
Adding 5 ounce of bleach brings the Chlorine back to 10PPM. I am puzzled. The water is perfect in appearance and no odours or anything negative...
I don't want to cure an non-existing problem, but I would like to understand it.
Thanks for any reaction.
Paul

 

[pooldv]

Welcome to TFP!

Maybe it is time to clean out the plumbing with some Ahh-some jetted tub cleaner. Otherwise, you could add more chlorine so that it lasts longer. Adding FC to 10 ppm isn't necessarily enough. It depends on bather load. You need to do enough chlorine so that there is 2-3ppm remaining next time you test.

Are you following this process?
How do I use Chlorine in my Spa (or pool)?

 

[ant 83]

I would not rely on the test strips, they're not accurate.

I'd suggest adding 30ppm cya, and see if that helps.