New pool owner, chlorine CC and FC too high, what to do?

[callmedpit]

I just purchased my home in November, it had a in-ground pool, and it's my first time having a pool. We had it professionally opened a few weeks ago.

Yesterday we had a couple friends over for the first time, all the girls noticed a burning/itching sensation, mostly on their legs. The two guys, nothing very noticeable, after being in the pool for hours.

This led me to believe that perhaps our chlorine was too high, plus I had not shocked the pool yet. So that evening I added shock (Doheny's - http://www.amazon.com/gp/product/B0051BI6UE/) and tested this morning. My test kit is a Taylor K-2006 (http://www.amazon.com/gp/product/B004BGF7TI/). The chlorine was off the charts, everything else seemed normal. Free Chlorine was 9.0ppm and Combined Chlorine was at 0.4ppm. My normal chlorine that I had been doing was putting 4 3" In The Swim tablets (http://www.amazon.com/gp/product/B002WKJ5R0/) in one of the skimmers, replacing when they were fully disolved.

From my understanding, there should be no combined chlorine, and even with the shock, it still tested at 0.4ppm.

Do you think that these high levels are what caused the skin irritation for the girls (assumed it was mainly on legs due to shaving)? What should I do at this point? Is it even safe to swim?

Thanks in advance for any help, I'm happy to answer any questions as well.

Update - Tested Water

FC = 2.5-3ppm
CC = 2.5ppm
pH = 7.4
TA = 100-110
CH = 380
CYA= 75

 

[duraleigh]

Welcome to the forum.

We can help but every pool water chemistry issue on this forum begins and ends with good testing. You have a fine kit so do the complete battery of tests so we have a good picture of your starting point. Post back to look like this...

FC = xxx
CC = xxx
pH = xxx
CH = xxx
CYA= xxx

 

[JohnT]

Welcome to TFP!

Without knowing your CYA, we can't really say. More than likely your chlorine was too low rather than too high.

We don't agree with the idea of routinely shocking a pool and we discourage the use of chlorine pucks because of the insane amount of CYA they add. Browse around Pool School to get an idea of our pool care philosophy.

 

[Richard320]

I just purchased my home in November, it had a in-ground pool, and it's my first time having a pool. We had it professionally opened a few weeks ago.

Yesterday we had a couple friends over for the first time, all the girls noticed a burning/itching sensation, mostly on their legs. The two guys, nothing very noticeable, after being in the pool for hours.

This led me to believe that perhaps our chlorine was too high, plus I had not shocked the pool yet. So that evening I added shock (Doheny's - http://www.amazon.com/gp/product/B0051BI6UE/) and tested this morning. My test kit is a Taylor K-2006 (http://www.amazon.com/gp/product/B004BGF7TI/). The chlorine was off the charts, everything else seemed normal. Free Chlorine was 9.0ppm and Combined Chlorine was at 0.4ppm. My normal chlorine that I had been doing was putting 4 3" In The Swim tablets (http://www.amazon.com/gp/product/B002WKJ5R0/) in one of the skimmers, replacing when they were fully disolved.

From my understanding, there should be no combined chlorine, and even with the shock, it still tested at 0.4ppm.

Do you think that these high levels are what caused the skin irritation for the girls (assumed it was mainly on legs due to shaving)? What should I do at this point? Is it even safe to swim?

Thanks in advance for any help, I'm happy to answer any questions as well.

Welcome!

9 FC shouldn't be bothersome unless CYA is very very low.That's unlikely if you've been feeding the pool trichlor pucks.
PH out of whack can irritate skin. The trichlor could have made the water very low pH - -acidic.
If the "shock" you added hadn't completely broken down, it can leave a chalky residue on the skin as well.

 

[callmedpit]

Welcome to the forum.

We can help but every pool water chemistry issue on this forum begins and ends with good testing. You have a fine kit so do the complete battery of tests so we have a good picture of your starting point. Post back to look like this...

FC = xxx
CC = xxx
pH = xxx
CH = xxx
CYA= xxx

I will re-test, but I had just shocked the pool last night, so it has been about 16 hours. Should I wait a certain period of time to let the shock work before testing for accurate results?

Also, just an FYI, PH levels tested last night were just fine at 7.6 I believe.

Let me know what you think about the appropriate testing time, and I will check all of the above items.

 

[JohnT]

I will re-test, but I had just shocked the pool last night, so it has been about 16 hours. Should I wait a certain period of time to let the shock work before testing for accurate results?

Also, just an FYI, PH levels tested last night were just fine at 7.6 I believe.

Let me know what you think about the appropriate testing time, and I will check all of the above items.

Without the CYA level, everything is an unknown. If your CYA is 100ppm, 9ppm is below the level you need to maintain, but if your CYA is 20ppm, 9ppm free chlorine is almost shock level.

 

[FamilyGuy]

If your fc is under 10 do a complete test for everything. If its over 10 wait till it drops and then test everything

 

[callmedpit]

Welcome to the forum.

We can help but every pool water chemistry issue on this forum begins and ends with good testing. You have a fine kit so do the complete battery of tests so we have a good picture of your starting point. Post back to look like this...

FC = xxx
CC = xxx
pH = xxx
CH = xxx
CYA= xxx

Ok, got a chance to test, let me know what you guys think:

FC = 2.5-3ppm
CC = 2.5ppm
pH = 7.4
TA = 100-110
CH = 380
CYA= 75

Again, this are results after shocking the pool, which we did after we realized the girls were getting irritated.

 

[Richard320]

Ok, got a chance to test, let me know what you guys think:

FC = 2.5-3ppm
CC = 2.5ppm
pH = 7.4
TA = 100-110
CH = 380
CYA= 75

Again, this are results after shocking the pool, which we did after we realized the girls were getting irritated.

CC of 2.5 would defintely irritate sensitive skin. What test kit did you use to get those readings? Oops, I see now.

Also, with CYA of 75, FC should never get below 6.

With CC at 2.5, you need to SLAM. If the water is otherwise clear, it should clear up really fast, possibly in just one day.

 

[callmedpit]

CC of 2.5 would defintely irritate sensitive skin. What test kit did you use to get those readings?

Also, with CYA of 75, FC should never get below 6.

I used a Taylor K-2006 test kit.

From what I understand, CYA is not really adjustable? It sounds like I'll need to raise the FC and decrease the CC, how would I go about doing that, and then maintaining the right levels. Am I doing the right thing by using the pucks (I put 4 at a time in the skimmer, replacing when they dissolve, for now the pump runs 24/7) and shocking every other week? I linked the actual products I use in my first thread.

 

[Richard320]

I used a Taylor K-2006 test kit.

From what I understand, CYA is not really adjustable? So from what I understand I'll need to raise the FC and decrease the CC, how would I go about doing that, and then maintaining the right levels. Am I doing the right thing by using the pucks (I put 4 at a time in the skimmer, replacing when they dissolve, for now the pump runs 24/7) and shocking every other week? I linked the actual products I use in my first thread.

The only practical way to lower CYA is by draining. You can stop making things worse if you quit with the pucks and powders.

Here's some of my best writing from last year. It will make more sense if you look at http://www.troublefreepool.com/content/128-chlorine-cya-chart-slam-shock

We'll take a 16000 gallon pool, because that's what I have. On a fresh fill, prominent national pool chain recommends 2.5 pounds pf stabilizer per 10,000 gallons, which works out nicely to 4 pounds which brings CYA to 30.

With an average loss of 2 PPM/Day or 14 ppm/week, I'll have added 8.6 PPM/CYA if I used trichlor pucks perfectly. And they recommend a weekly "shock" of dichlor between 5 and 10 FC.... 2-3 oz per 10,000 gallons. Split the difference; I'll add 4 oz. CYA went up another .9.

So..by the end of week one, I have added 9.5 more CYA. It is now 39.5. Mimimum FC for that is 3, so I'm probably okay.

Week two, up to 49 CYA.
Week three, 58.5. Minimum FC should be 5, but they recommend 3 as ideal, so the pool looks a bit hazy. So I'll toss in a little extra dichlor "shock" to jack FC up to 10. Which adds another 6.4 CYA. Keeping count? We're up to 64.9 now.

That caught the algae just in time.. we had two weeks of good luck. A steady diet of pucks and 4 oz. "shock" each week only added another 19, up to 73.9 now.

Week 6 it started looking funky, so we "shocked"it once again. CYA is up to 99.3. But minimum FC to keep algae at bay is 8, and we're still holding things to 3, because prominent national chain's preprinted sheet shows that as ideal. So algae got a toehold and the pool has a bit of a tint. So we throw two whole bags of dichlor in which jacks it another 7.6 by the time week 7 is over, we're at 116.4, because we had pucks in the floater the whole time.

So...in 7 weeks, from 30 to 116.4. Let's say there are no more algae outbreaks because they sold me a huge bucket of phos-free and another of yellow-out monopersulfate "shock" Nothing but the pucks and the extra 4 oz of dichlor "shock" weekly. So the next 7 weeks added 66.5, which brings the total to 182.9 CYA.

Now if we didn't understand this and things looked a bit hazy, we might throw an extra puck or two in the floater every couple weeks, which will drive it over 200 easily.​

 

[iadams]

I just want to say welcome, and give some advice that I (surprisingly) didn't see yet. You really should read the Pool School info. It will cover a lot of your questions and concerns.

I also notice you used the word "shock" a lot, and I have a feeling you are using it as a noun as much as a verb. Shock is something you do to your pool, by raising the FC to the appropriate level based on your CYA reading. Even though the bag or bottle says so, the product inside is not shock, because simply adding random amounts of it does not bring FC to shock level. One of the most important things I learned here is that shock is an action, not a thing.

With that CYA, definitely stop using the pucks before you have to do a partial drain and refill to bring CYA down. Get yourself some liquid chlorine, such as plain old bleach, read pool school, and if you have a smart phone you can download one of the apps that help you decide how much bleach to add.

I am in Mt. Airy MD, so we have similar weather. You may lower CYA over the next month just by dilution from rain water if you end up getting a lot of rain and needing to dump water to bring the level down. Otherwise, it probably isn't much to worry about at 75.

Just out of curiosity, where did you get the water to fill it up when you opened? Does it have a Salt Water Generator?