Safety of swimming in high chlorine levels after shock

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uwaeve

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Jun 26, 2013
12
Groton, MA
Question about chlorine level after shock, I'm basically trying to figure out when we can go in my pool. Short story: CC levels are at 13 after a shock, with the rest of the chemistry (details below) seemingly nominal and sparkling blue water.


Backstory on pool in my signature:

Had wall repaired and liner replaced, then filled pool with 60% well water and 40% delivery a week ago.

Got filter running, added correct amount of DE. I have run the pump constantly since starting it up, with the pressure looking good and getting strong flow at the inlet.

Last Saturday took a water sample to local pool store (I don't have the results with me but it's basically what you'd expect for fresh water, also zero iron and 0.3 [g/ml?] copper), paid $120 for probably $10 of grocery store chemicals, followed their instructions. They are a BioGuard dealer for what that's worth. They suggested not treating for the copper at this point, if that matters. I said I had some 1 lb shock packs at home so their instructions ended with 2 of these to shock. So Sunday night I tossed 2 of the packs in and brushed up the stuff that settled. This is in addition to the 2 Silk Smart Sticks in my skimmer that the instructions told me to add before all the other steps. Possibly relevant is that the sticks had pretty much dissolved and I have still been finding undissolved something on the floor that I brush up when I see it. I held off on adding any more of the chlorine Sticks as I feel like I'm trying to get the chlorine levels down at this point. Let me know if I need to add them either now or before I get down to the maintenance level, I understand I probably don't want to go to zero before adding them.

I had a TF100 test kit coming in the mail on Tuesday, so I was just generally monitoring with pool store generic test strips, which showed the chlorine pegged at 10 (the highest reading), which is the only info I have from before Tuesday night (last night), when I got home to run a proper test.

Results are:

Temp 78
FC 13
CC 0.5
pH 7.65 (really just between 7.5 and 7.8)
TA 160
CH 140
CYA 32.5

The pool has been sparkling blue the whole time, and we've had overcast weather and thunderstorms and lots of rain (actually had to take about 2" of water out last night) since Sunday (we're outside Boston if that's important). Never had a real strong chlorine smell (I understand the smell is not because of "too much chlorine," but thought it may be relevant).

I guess I'm overall happy with the results, but the family kind of wants to swim seeing as how it's 4th of July and 90 out.

I am assuming the chlorine levels are coming down as I didn't have a big boy test kit to see what the initial shock levels were, and perhaps it has been coming down slowly due to not much sun.

I have read that commercial pools may be chlorinated to levels similar to what I have. My son's hair is also very light blonde so I don't want to be the one to make the call that gives him green hair, as I will never ever live that down. I am OK ruining old bathing suits. Obviously actual health and safety are primary but I'm guessing at 13 PPM my kid isn't going to dissolve in the pool.

Thoughts?
 
Welcome to TFP.

You're trying to be way too precise on the numbers. If the pH is between 7.5 & 7.8 just call it 7.6 or 7.7 pH. I assume you did the same thing on the CYA. I'd call it 30.

Green hair does NOT come from chlorine! It comes from copper in the water. So that's something you don't have to worry about as long as you haven't added anything like algaecides with copper in them. If you have, then you have to worry about it regardless of the chlorine level.

Having said that, it's prefectly fine to swim up to shock level for your CYA. At 30 ppm CYA you're ok to swim at 13 ppm FC.

OOPS: I see you have copper listed in the post. You're either going to have to drain an refill to get that as low as you can or you're going to have to use sequestrant from now on. That has nothing to do with the level of chlorine you have. :(
 
IMHO, 13 is pretty close to your shock level of 12. The sun and increased bather load is going to consume your FC. It's likely going to be 12 or less by the time you have your kids in the pool.

I say swim!

As to the green hair, that is more a factor of copper, than chlorine (IIRC)
 
Chlorine is not the cause of green hair. Metals in water are, especially copper.

It is safe to swim up to shock level, and at 13 you are right on the edge. I see no issue with it.

I bet you see a different CYA level when you test with your TF-100, compared to what you have posted above. :)

"A shock", that has me wondering what you did. A true shock is a process, not a single addition of a product. If your pool was sparkling, why would you mess with the shock process or a shock product?
 
Thanks for the quick replies!

To be clear, the test results I posted are using the TF100. Which says if something's between two numbers, average them :) I understand hundredths are not significant for pH measurement.

Looks like I got misinformed, I understand now that it's metals that will change hair color.

The pool store recommended to see how things went with getting the pool balanced and running before addressing copper. It sounded like if it wasn't causing issues like precipitation upon addition of other chemicals, it may be OK to leave as is. I don't think a drain and refill is going to help, as the copper is not from an algaecide but from either our well water or the trucked delivery, which is what I would be refilling with if I drained and refilled. The copper results of 0.3 mg/L were from the sample taken before I put any chemicals in, as measured by the pool store.

Maybe I'm misusing the word shock. The final step in the pool store instruction sheet said to add 2 1-lb bags of chlorine treatment, which I said I had at home.

My plan is to continue to read and learn and hopefully be able to do the balancing and maintenance myself without relying on the pool store. But when it's been a 2-month odyssey to get the pool repaired and filled, and it's 90 out, I kind of just wanted to get the kids in the pool. I don't think they'd understand "Maybe we can use the pool in August after daddy figures out what he's doing."

Appreciate the advice and I will update as things fall apart on me :)
 
Regarding shocking the pool, our goal is for you to understand it is a process you go through when you have a problem, such as an algae outbreak. There is no other reason to shock your pool. You don't need to do weekly or bi-weekly additions of shock products, in fact several of us have gone years without shocking our pools.
 
The bags of "shock" are simply solid forms of chlorine, with a few additional chemicals. Typically they have a stabilizer (CYA) and some calcium. Unless you need to add CYA to your pool, you are better off using liquid chlorine (LQ) or bleach to maintain the FC levels in your pool. LQ doesn't effect the other levels in your pool making it much easier.

You only need to shock when your daily testing indicates you have a CC of 1ppm or you see a difference in the clarity of the water. When I get my pool BBB clean, I can see the difference between "clean" and "needs a shock" before the testing confirms it.
 
Right, I can see and smell it. I can tell a pool that's not balanced right away. Thus my quote in another thread regarding not getting into hotel pools. I usually don't get in friend's pools either, unless they are one of my close friends that asks me to bring my test supplies over when I go. :) I'll be getting in a friend's pool tomorrow, but he follows BBB religiously, and I totally trust his water.
 
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