Chlorine down to zero

[Caffrin]

Hi all! I have an above ground pool and finally understand how to keep it crystal clear (thanks to this group!)
I’m out of town visiting my parents who have a hot tub (that is always covered). They haven’t been heating it and the chlorine was at zero so I poured some liquid bleach yesterday for now and measured it at 3ppm. They don’t have a great tester here so I’m forced to use what they have. The chlorine is currently at 3ppm after 24 hours. I don’t know much about hot tub water chemistry and I realize with a cover and no sunlight they won’t get algae (which is my indicator in our pool that’s something is wrong with the water.)
My question is, is bringing it up to 3ppm good enough to kill any potential bacteria? Should I shock it higher? I have no way to test the CYA here.

 

[Texas Splash]

I'm afraid without a full and reliable set of water test results it's all a guessing game. An FC of 3 ppm may not be much when the CYA is 30 or more, but is much more potent if the CYA has fallen close to zero. Lots of variable to consider. Even with a cover bacteria can grow, so be careful of that as well.

 

[Caffrin]

I'm afraid without a full and reliable set of water test results it's all a guessing game. An FC of 3 ppm may not be much when the CYA is 30 or more, but is much more potent if the CYA has fallen close to zero. Lots of variable to consider. Even with a cover bacteria can grow, so be careful of that as well.

That’s my concern, bacteria. My mom is immunocompromised so I don’t want her getting in if there is bacteria in the water. I just don’t know if getting it to 3 after being at zero for who knows how long is enough to kill anything in the water. Maybe draining it would be a better choice?

 

[Texas Splash]

Maybe draining it would be a better choice?

At this point, given the medical issues with your mom, I would say so. Even better if you had the time and a few additional $$ to spend on an Ahh-Some treatment to purge the system clean. Then you could start over from scratch.

 

[Texas Splash]

Here's a great link if you haven't seen it already.

How do I use Chlorine in my Spa (or pool)?