Itchy skin in spa

[nismosao]

I am a newbie to pool ownership. Our pool just got completed in late December so it’s too cold to use. We have been using the heck out of the spa though. The last couple of times I’ve come in, I have noticed that my legs feel very itchy as soon as I enter.

I read some threads where it was stated that high chlorine levels could do this. While my FC is on the elevated side (about 5ppm and I have my SWG turned to off right now), my TC is the same. It doesn’t seem ridiculous.

I’m testing with a TF-100. Any ideas what the issue may be? See below for screenshot of levels.

 

[Newdude]

Hey Nismo and belated Welcome !!!

I read some threads where it was stated that high chlorine levels could do this. While my FC is on the elevated side (about 5ppm

Your FC isn't high with a CYA of 60. It buffers the FC and its entirely safe up to SLAM level / 40% / 24 FC. Tap water with 0 CYA and up to 4 FC is more harsh than your pool water, so if you can shower without issue, it's not the chlorine.

You mention the SWG is off. How are you chlorinating ? How often ? If this were a traditional hot tub and not a spa we'd point to bacteria / hot tub rash from letting the FC levels dip. Spa bather load is off the charts and needs lots of sanitation to match it. If the SWG is off and you're not exchanging the water with the pool, it's probably responding like a hot tub that isn't sanitized enough.

 

[Mdragger88]

Are you using the fas/dpd test? The one with drops & powder that turns pink then clear.
You should have results for
FC (good stuff)
& cc’s (bad stuff)
Fc + cc = TC
The OTO test (yellow drops in the comparator block) is not very accurate as it only measures TC & only up to 5ppm.

 

[nismosao]

Yes, I turned the SWG off to get it in more acceptable ranges. It’s only been off for about 2 days. I’m of the understanding that FC levels should ideally be about 3.6ish, correct?

 

[nismosao]

I am using the FAS test to determine that it’s 5 FC and 0 CC. I do check it using the OTO test daily, but it’s always off the chart.

 

[Mdragger88]

Has your fc dipped below minimum for your cya at anytime?
FC/CYA Levels
5ppm can be easily used up by a 2 person extended soak, you must check the fc before & after use & ensure you never fall below minimum lest nasties will grow & you’ll be playing catchup.

Is this a covered standalone spa?

 

[Newdude]

I’m of the understanding that FC levels should ideally be about 3.6ish, correct?

You can't possibly skin it that accurately. 4 is your target but a couple minutes in a steaming hot tub will leave you below minimum for the rest of the time. The residual soaps, sweat, body oils, etc will fester and bite you next time.

You need to start the soak with enough FC to get through the soak, then leave enough FC behind for whatever ickies you left behind, and verify with a test right before the next soak that you're covered again. The SWG can handle the overnight maintenance, and i'd dose the FC to 12(?) before and after the soak.

 

[nismosao]

Has your fc dipped below minimum for your cya at anytime?
FC/CYA Levels
5ppm can be easily used up by a 2 person extended soak, you must check the fc before & after use & ensure you never fall below minimum lest nasties will grow & you’ll be playing catchup.

Is this a covered standalone spa?

Thanks. I didn’t know about the FC CYA chart. That makes me feel a little better.

No, this is a spa that overflows into the pool.

 

[nismosao]

You can't possibly skin it that accurately. 4 is your target but a couple minutes in a steaming hot tub will leave you below minimum for the rest of the time. The residual soaps, sweat, body oils, etc will fester and bite you next time.

You need to start the soak with enough FC to get through the soak, then leave enough FC behind for whatever ickies you left behind, and verify with a test right before the next soak that you're covered again. The SWG can handle the overnight maintenance, and i'd dose the FC to 12(?) before and after the soak.

Dang, so you guys think I’m actually more low than too high? I had no idea about checking prior to getting in. Interesting.

Thanks for the replies all.

 

[Newdude]

The CDC is now reccomending 3 - 10 ppm FC for spas, not factoring in the CYA. We know you can go to 24 with a CYA of 60.

Hot Tub Rash | Healthy Swimming | Healthy Water | CDC

Education and information about hot tub rash, how it can be spread through hot tubs, swimming pools, and other recreational water, why it's important to protect yourself from it and steps for doing so.

www.cdc.gov

 

[Mdragger88]

Are you currently mixing the pool & spa water?
Does the spa have its own filter separate from the pool?
If not mixed or if only rarely since it’s winter & heating it up can be costly then you may need to treat it more like a standalone & give it an fc boost with liquid chlorine to be certain you’re maintaining adequate fc at all times.
If it shares a filter with the pool then you need to be certain you’re mixing them regularly so the spa water gets filtered, this will also help chlorinate the spa but affect the temp.
If you’re regularly mixing, but aren’t able to maintain fc either increase that frequency with your automation or as mentioned above you can always add a boost with liquid chlorine if needed.