Oxidizing Shock Questions

[bagelbagel]

Third year of using my Precision 7 Hot Tub. This forum helped me move from using the Frog Ease Ball and onto the Bleach method. Made my hot tub maintenance so much simpler. We only use our hot tub during the Fall/Winter/Spring time, and it is covered when we are not using it. My questions related to dealing with Combined Chlorine (CC). I normally use Oxidizing Shock weekly, 3 oz for my 400gallon tub (instructions on the container). I test at home but when I take my water into the spa store, they usually recommend me add more. I want to get this all down, so I need some clarity.

I assume keeping the spa covered when not using causes more CC to stay in the spa?

Is it ok to just keep using more oxidizing Shock to keep those CC levels down?

If I’m finding I keep needing to use the oxidizing Shock to keep CC down, is that a good sign I should drain the tub?

Appreciate the help, and my spa water is always very clear. Immensely better results than using the frog ease ball.

 

[proavia]

Which of the recommended test kits are you using ?
Test Kits Compared

Post a full set of current test results from that test kit.

FC
CC
pH
TA
CH
CYA
Water temp

 

[bagelbagel]

FC 12.5
CC 1
PH 7.2
TA 70
CH 200
CYA 60
101 F

I added 4oz oxidizing Shock yesterday. And probably too much chlorine.

 

[JoeSelf]

MPS will show up as CC. What chemical is in your"shock" .

 

[bagelbagel]

MPS will show up as CC. What chemical is in your"shock" .

It’s spa pure oxidizing Shock, so looks like MPS. Also forgot to say I use Taylor K-2006C for testing.

 

[Mdragger88]

Mps isn’t necessary.
Mps is only an oxidizer.
Chlorine is both an oxidizer and a sanitizer when used in appropriate amounts.
Chlorine alone can do the job.
Persistently elevated cc’s above 0.5 are a sign that its time for a purge, drain, & refill.
As mentioned above MPS can show up as cc’s when testing if the interference reagent isn’t used.
This can cause confusion.
Either discontinue MPS use
Or
If you wish to continue MPS use get the R-0867 interference reagent so you can accurately assess the health of your water.
Leaving the cover off a bit after use/dosing & occasionally when the tub is not in use will help let the cc’s out. It is also recommended that you do this to prevent degradation of your cover.

 

[bagelbagel]

Ended up doing a fresh refill.

Of my hot tub is always covered and generally never exposed to UV. Do I need to use much dichlor to raise CYA? Or can I just use liquid chlorine?

 

[Newdude]

You'll want 20 or 30 CYA for bather comfort. Unbuffered chlorine is harsh on the skin.

 

[Mdragger88]

You'll want 20 or 30 CYA for bather comfort. Unbuffered chlorine is harsh on the skin.

And equipment like head rests and the cover.
Since its hard to get an accurate reading on anything under 30 I like to aim for 30-40 ppm. In a hot spa the cya degrades over time so this keeps you in the ok zone for a bit