Very high combined chlorine

joshf

Member
May 1, 2019
13
Austin, TX
The quick summary is that I currently have 0.4 Free Chlorine, and 22ppm Combined Chlorine (using Taylor K-2006 FAS-DPD test kit). I have never seen anything like that before, nor any online posts mentioning CC that high. Now I'll give the longer story of how I got to this point. I don't know how much is relevant, so I'll tell everything.

I bought a new house with a pool last year. As part of the sales contract, the previous owner had the pool resurfaced. What I gathered after the fact is that resurfacing a pool should involve someone attentively taking care of it for the first 30 days after - but I'm pretty sure that did not happen (we did not own the house yet). When we got in, we noticed the pool walls were very rough - like sandpaper. If you rubbed them too hard, it could draw blood. I asked around for advice - one person told me to dump some bottles of Jack's Magic Blue stuff in and it would clear up.
I called Jack's Magic to get their take, and they directed me to take their stain identifier test. I did that, and the #2 (Copper and Scale) did smooth out the wall at test spot. So that seemed like a promising solution, and they gave me specific instructions on what to do:
- first get the calcium hardness down. I was getting readings between 500-600. Will need to drain and refill some of the water
- when refilled, balance to less than 7.4pH, get TA down less than 80ppm, and FC between 1-3.
- when we are at pH7.4, add another gallon of muriatic acid
- then add 2 full bottles of Jack's Magic Magenta (not blue, as the instructions state)
- then add 15 lbs of Jack's Magic #2 Copper and Scale
- keep adding acid to keep pH and TA down
- run pump 24/7. watch filter pressure. if it goes up by 5lb, backwash it. this will happen often
- keep brushing it
- cannot use pool during treatment. should be about 2 weeks
- bring TA back up when done

So the time I figured all of that out, it was late May and full swimming season. I did not want to drain the water and lose usage for a few weeks, so I decided to wait until next year. The water was crystal clear - just the walls were annoying.
Now it is a year later. Early in April, once it was warm enough (about 65), I drained about half of the pool and refilled. Got it to the balance they suggested, and then followed the rest of those instructions.
After about 2.5 weeks, I thought it was about done. The filter wasn't getting backed up as fast as earlier. However, the walls were not much better.
I decided to give up on the walls - I wanted to get the pool ready for swimming. The pH was low so I tried adding liquid chlorine (I had used dichlor all last year until I learned about CYA). The FC stayed low, but my CC was high - about 5ppm. Went to the pool store, and they wanted me to shock it. Had me put about 20lbs of baking soda in the pool to get the TA back up (5lbs every 2 hours). Then dumped 5lbs of calcium hypochlorite in, which I had never used before. It made the pool very cloudy - I had never seen that before. After it cleared up, there was white powder on the pool floor. I kept brushing it, and it would get cloudy again. It eventually cleared up for good. That's when I started seeing readings above 15 CC. Went back to the pool store, and they sold me some chlorine eliminator. Said to put 2/3 of the bottle in, and it should bring all the chlorine down to 0 in a couple hours, then I should shock it again. Well, the chlorine eliminator seemed to have no effect at all. I dumped the rest of the bottle (2lb total), still no luck.

My filter is still getting blocked up pretty quickly. It has gone up about 3lbs since I last backwashed it 2 days ago. I think I only backwashed it twice all of last season. This makes me think the sequestrant (Jack's Magenta) is still interfering, holding on the CC - but that's just a guess based on bits of information I've picked up. I continue to run the pump 24/7.

I'm at a loss on where to go next. I've read the SLAM procedure, but that seems to refer to algae issues. I don't have algae issues - my water is perfectly clear. I just need to get rid of the combined chlorine to get it to safe levels. All last season I never saw higher than 0.4CC, so getting measurements at 22ppm just seems crazy. Especially when I read I need to use 10x that amount to shock it. That's a lot of chlorine. I was always skeptical of the pool stores, and now even more so.
Is this something I have to wait out? Do I need to dump water again? I'm not sure I have anywhere safe to dump water with that much chlorine in it.
Or is there something I can do to actively get it back in control?
Any advice would be appreciated.

-Josh

Pool: 15000 gallon in ground, white quartz plaster. DE filter. single speed pump.
 

splashpad

Bronze Supporter
Aug 2, 2017
1,981
SE Kansas!
I'm at a loss on where to go next. I've read the SLAM procedure, but that seems to refer to algae issues. I don't have algae issues - my water is perfectly clear. I just need to get rid of the combined chlorine to get it to safe levels. All last season I never saw higher than 0.4CC, so getting measurements at 22ppm just seems crazy. Especially when I read I need to use 10x that amount to shock it. That's a lot of chlorine. ...
Is this something I have to wait out? Do I need to dump water again? I'm not sure I have anywhere safe to dump water with that much chlorine in it.
Or is there something I can do to actively get it back in control?
Any advice would be appreciated.
Another link Rebalancing after Jack's Magic #2 (it's also in that thread James shared too) Basically you can wait it out or fight it. Fighting it seems to go "quicker", but it's aggressive.

I was always skeptical of the pool stores, and now even more so.
This is a very true statement and why I'm thankful TFP info & forums exist!

Pool: 15000 gallon in ground, white quartz plaster. DE filter. single speed pump.
Can you put this info in your signature, please? Thanks!
 

mattchase00

In The Industry
Feb 27, 2019
26
Largo, FL
From someone who knows a little about Jack's Magic :) The #2 contains Nitrogen this causes the CC. Just read total CL2 for 3-4 weeks and free reading will snap back when Nitrogen gasses off...

Matt
 

TexasPool128

Well-known member
Apr 22, 2019
47
N. Texas
Nitrogen in what chemical?

Are you saying that it's not sulfamic acid?
It says he’s “in the industry”, he says he’s “someone who knows” and he’s from “Largo, Florida” (where Magic Jack’s is). Maybe he knows something others don’t?
 

JamesW

TFP Expert
Mar 2, 2011
14,551
Sulfamic acid is H3NSO3

The chlorine substitutes for the hydrogen to form the CC.

A single substitution forms monochlorosulfamate. A double substitution forms dichlorosulfamate.

The nitrogen is in the -3 oxidation state like in ammonia. So, breakdown is oxidation of the nitrogen to nitrogen gas.
 
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joshf

Member
May 1, 2019
13
Austin, TX
Thanks a lot for the links - that helps a lot. I hadn't found anything before because I didn't realize it was directly related to Jack's Magic - I just included that detail just in case. Nobody at the pool store that sold me the stuff put it together when I mentioned my problem. I'll follow up with Jack's Magic, they were really helpful in diagnosing the scale issue, so I'll see if I still have a chance of addressing that before I try to aggressively attack the CC.
 
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joshf

Member
May 1, 2019
13
Austin, TX
Ok, so I've been following the CC number for now since my FC readings aren't correct. But the last few days, the tests have been confusing. After adding about 10 drops (of 0.2 each) it goes clear for a second and then pink returns. I keep adding drops and it goes clear and lasts a little longer, but pretty quickly comes back. It isn't until I get to about 35 drops that it stays clear. So should I read that as 2ppm or 7ppm? I have never had that problem in the past with this same test kit, so I assume it has something to do with the altered state of my water rate now.
 

JamesW

TFP Expert
Mar 2, 2011
14,551
The iodide in the water can be turned into iodine by oxygen in the air.

Just go by the first time the sample goes colorless (clear).

Also, use the 10 ml sample where the multiple is 0.5 per drop.
 
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joshf

Member
May 1, 2019
13
Austin, TX
It it "normal" for FC to drop 6ppm? I have beautiful clear water. Considering the testing complications mentioned already (FC does not show up, only CC, and test goes clear pretty quickly, but turns pink again in seconds), I can't tell if I should be adding this much chlorine every night. For example, the last few nights, I've measured 2.5-3ppm chlorine (using the CC number as FC). So I add 96oz - 1 gallon of 10% liquid chlorine. It usually tests around 7.5-8ppm in the morning. By evening, it is down to 2.5-3ppm again. Is that just normal burn off?
This is my first year using liquid chlorine. I'm used to just putting 3 tablets in the chlorinator and not thinking about it for a few days. If the liquid chlorine approach means adding 1 gallon every night, it seems like it will be much more expensive.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
It usually tests around 7.5-8ppm in the morning. By evening, it is down to 2.5-3ppm again. Is that just normal burn off?
Hey Josh! :wave: No, it is not normal, but then after reading your thread, neither is your situation. Pool store advice didn't help your cause either I see. But James is watching you closely. Until your pool sheds the residual from the Jack's products, you'll need to be somewhat aggressive with the chlorine/bleach to keep that FC in your target zone, otherwise you will definately have an algae issue on your hands. Temps in our area are slowly rising, so the FC will be important. Just stay far away from any cal-hypo products or tabs.

It's been a while since you posted full results, so that may be helpful next chance you get. Not sure where you get your chlorine up there. I use to go to HEB but their % strength dropped to 6% (but not the price per gallon) so I stopped going there. I got my last few batches (10%) from Home Depot. Make sure to have a few bottles on-hand and ready.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
6,038
Northern NJ
It says he’s “in the industry”, he says he’s “someone who knows” and he’s from “Largo, Florida” (where Magic Jack’s is). Maybe he knows something others don’t?
See @mattchase00 Intro post Technical Support/Commercial Specialist

Just wanted to introduce myself. My name is Matt, I am Technical Support /Commercial Specialist at Jack's Magic Products based in Largo FL. I may be able to assist with Pool Staining challenges?
 
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joshf

Member
May 1, 2019
13
Austin, TX
------------------------------------------
Test Results 05-17-2019 @ 08:21 AM
------------------------------------------
Free Chlorine: 7.0
pH: 7.8
Total Alkalinity: 80
Calcium Hardness: 375
CYA: 50
Temperature: 79°F
CSI: 0.20
 

joshf

Member
May 1, 2019
13
Austin, TX
Well, the numbers usually hold pretty well overnight. I added a gallon of 10% at around 9pm last night. If the pattern holds, the FC will be down to 2.5-3 by 8pm tonight.

And to be clear about my measurements today: it took 4 drops (0.5 ppm) for the initial pink to go clear. Then I added 5 drops of the reagent to measure CC and then it took 10 more drops for that to go clear. So if it weren't for my weird situation, I would normally record that as 2ppm FC and 5ppm CC. But as advised in this thread, I am treating the total chlorine as the FC.
 

mattchase00

In The Industry
Feb 27, 2019
26
Largo, FL
This is way too complicated :) You are doing it right... totally disregard free and treat total as free.. You are not going to break up #2 by adding CL2. Just be patient free will snap back.. I just did a 300,000 gallon Resort Pool with 300 lbs. of #2 took six weeks for free to come back.
 
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joshf

Member
May 1, 2019
13
Austin, TX
Thanks for the reassurance on the measurements, but is the #2 causing the pool to eat chlorine so fast? As I predicted, those readings from yesterday morning dropped drastically by night again. When I put the DPD powder in the test water at 10pm last night, the water didn't even turn pink. After adding 5 drops of R-0003, it turned slightly pink, which went away after 3 drops of R-0871 (in 10mL sample). That is a whole gallon of 10% from 24 hours ago down to 1.5 FC.
 

joshf

Member
May 1, 2019
13
Austin, TX
Well everything is back to normal now! I read 4ppm FC last night (true FC measurement, before adding the R003), and 0 CC.
Thanks for the help and reassurance.
 
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