Indoor, in ground pool high combined chlorine

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I’m still waiting for my test kit to arrive (seems delayed from the post office due to upcoming Thanksgiving holiday maybe?).

In the meantime, I’ve been adding 1 gallon of 7% liquid chlorine bleach every 2 days or so. And I added 32oz of AquaDoc’s phosphate remover while no one was going to be around since my phosphates were over 4000.

I stopped by the pool store today to test the water (just to see any changes while I wait for my Test Kit to arrive and then SLAM my pool).

I haven’t added anymore chlorine tabs or any other chemicals other than the bleach and the phosphate remover per the advice of this group.

Results today (number in parentheses was prior value on 11/13):
Free chlorine: 0.5 (0.6)
Total chlorine: 8.7 (6.6)
pH: 7.6 (7.5)
Total alkalinity: 118 (133)
Calcium hardness: 115 (93)
CYA: 49 (45)
Optimizer: 11 (11)
Phosphate: 3214 (4000+)
TDS: 1500 (1600)

So the combined chlorine is ever worse now. Am I reading the Pool Math app correctly — it says to SLAM my pool my FC target is 19. So for my 17k gallon pool with a CYA of 49, I need to add 4.2 gallons of 7.15% chlorine liquid bleach.

Thanks for all the help!
 
I haven’t used any stain removers. And I doubt the phosphate remover had sulfamic acid in it.

Attached are pictures of the pool and equipment. As you can see the pool water is crystal clear, but seems to have a sheen on the surface.

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The CC level seems unlikely unless you have something in the water.

Let's see what the new test kit shows and what happens when you begin the SLAM.

Is there any noticeable smell?
 
When the cover is off, there is a very chlorine-heavy smell that develops pretty quickly. Which provokes a cough and watery eyes for anyone in the room for more than 20 minutes.

I’ll post the test results with the kit when I get it and go from there. What else would be in the water that’s causing the high CC?
 

CC - Further Reading

www.troublefreepool.com www.troublefreepool.com

Some chemical compounds, such as potassium monopersulfate (a common non-chlorine shock used in hot tubs) or sulfamic acid (an organic acid used to remove calcium and metal scale) will show up on the chlorine tests as CCs.

Free Chlorine testing after using Sulfamic Acid is discussed in Acid#FC_Testing_After_Using_Sulfamic_Acid.

Potassium Monopersulfate Compounds aka MPS or "non-chlorine shock' will interfere with the Combined Chlorine test. Taylor Technolgies has the R-0867 Deox Reagent that will neutralize MPS effects on the CC test. R-0867 Deox Reagent is available in the K‑2041 (.75 oz) and K‑2042 (2 oz). It’s also available as a stand-alone kit, the K‑1518 FAS-DPD chlorine/monopersulfate test.
 
ajw22 said:

CC - Further Reading

www.troublefreepool.com www.troublefreepool.com

Some chemical compounds, such as potassium monopersulfate (a common non-chlorine shock used in hot tubs) or sulfamic acid (an organic acid used to remove calcium and metal scale) will show up on the chlorine tests as CCs.

Free Chlorine testing after using Sulfamic Acid is discussed in Acid#FC_Testing_After_Using_Sulfamic_Acid.

Potassium Monopersulfate Compounds aka MPS or "non-chlorine shock' will interfere with the Combined Chlorine test. Taylor Technolgies has the R-0867 Deox Reagent that will neutralize MPS effects on the CC test. R-0867 Deox Reagent is available in the K‑2041 (.75 oz) and K‑2042 (2 oz). It’s also available as a stand-alone kit, the K‑1518 FAS-DPD chlorine/monopersulfate test.
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Great info. I used 8 oz of BioGuard Pool Magnet Plus which according to its MSDS sheet has phosphonic acid and etidronic acid.

The smart shock I was using is BioGuard Smart Shock which isn’t MPS shock.
 

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i_intub8_u said:
Great info. I used 8 oz of BioGuard Pool Magnet Plus which according to its MSDS sheet has phosphonic acid and etidronic acid.
Click to expand...

The Phosphonic Acid and EDTA is breaking down and creating the phosphates in your water.

Sequestrant - Further Reading

www.troublefreepool.com www.troublefreepool.com

Why are you using that?

You are creating a cycle of unnecessary chemicals.

i_intub8_u said:
The smart shock I was using is BioGuard Smart Shock which isn’t MPS shock.
Click to expand...

The Bioguard Smart Shock contains copper citrate which will accumulate in your pool water and eventually cause staining, if it has not already.

You should not be using any product that contains copper or has "blue" in its name which is a code word for copper.

Bioguard products are overpriced and contain unnecessary and unwanted chemical additives.
 
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i_intub8_u said:
I haven’t used any stain removers. And I doubt the phosphate remover had sulfamic acid in it.

Attached are pictures of the pool and equipment. As you can see the pool water is crystal clear, but seems to have a sheen on the surface.

View attachment 541545View attachment 541546View attachment 541547View attachment 541548View attachment 541549View attachment 541550View attachment 541551View attachment 541552View attachment 541553View attachment 541554
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Welcome! Be careful which bleach you use. Nearly all of the grocery store bleach has fabric softeners, scents, etc that you don’t want in the water. You said there’s a sheen on the surface and I wanted to make sure you check. The bleach must be plain.

Many people use chlorinating liquid from a hardware store or Walmart as those are higher concentration and have no additives.

It will be fun to see how not very accurate the pool store testing has been. It’s always hard to believe that they are that bad at testing (and giving advice) but your pool service seems to take the prize.
 
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ajw22 said:
The Phosphonic Acid and EDTA is breaking down and creating the phosphates in your water.

Sequestrant - Further Reading

www.troublefreepool.com www.troublefreepool.com

Why are you using that?

You are creating a cycle of unnecessary chemicals.



The Bioguard Smart Shock contains copper citrate which will accumulate in your pool water and eventually cause staining, if it has not already.

You should not be using any product that contains copper or has "blue" in its name which is a code word for copper.

Bioguard products are overpriced and contain unnecessary and unwanted chemical additives.
Click to expand...
This is their (the pool store’s) primary game- sell you copper containing products then turn around & sell you sequestrants to “cure” the problem they created in the first place.
@i_intub8_u It’s Time to break the cycle 🔄!
 

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And...from the pictures, I suspect algae growing (main drain/step colors. Perhaps a color cast on the sides/floor - but that could just be the general lighting). How easily does it brush off? Do you get any "poofs" or clouds when brushing? That too could give a color to the water, and a film on the surface.

But first we wait for your test kit and home test results, and getting the rest of the witches brew under control....
BTW - if you have a Menards near you, they too sell pool chlorine gallons at an affordable price. Buy 2-4 cases to start.
 
JamesW said:
The color of the main drain grates points to a metal issue.

View attachment 542018

The most likely metal is iron, but there are several different metals that can cause staining.

As for any CC levels, I do not have any confidence in the reported levels from the pool store.

Until the OP gets their own good kit, the FC, CC and TC numbers are pretty much useless.



Blue algaecide is probably copper.

The film points to some sort of unidentified contaminant.

Maybe some sort of oil.





The Reports from the swimmers clearly indicates some sort of contaminant.

If the CC numbers are confirmed, then the only thing that I know of that will produce that level of CC is sulfamic acid.

Sulfamic acid might, or might not, have been added.

I do not think that we know for sure everything that has been added.

I suspect that the well water contains some sort of contamination, but there is insufficient information to identify what the contaminant is.

I would recommend finding a qualified lab that can do a comprehensive set of tests to identify what is actually in the water.
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I was out of town for Thanksgiving, so just getting back around to tackling the pool. Yes, the well water where I am is known to contain high iron levels. I have an iron filter on the house/domestic water, but that filter is after it feeds the sprinkler irrigation system and the pool water fill. So that makes a ton of sense that iron is the culprit for the green tinge I was dealing with and the staining of the grates.

I got my TFTPro test kit and just did all the tests. Here are the results:
Chlorine drop test:
FC 2ppm
CC 8ppm
TC 10ppm
Ca hardness 175
TA 170
CYA between 40-50 (I added a few more drops and couldn’t see the black dot, so leaning more towards 40).
pH 7.8 (maybe a tinge lighter so 7.7?)

Also, I’ve been making sure the bleach I buy is unscented pure liquid bleach from Walmart and Sam’s club. Ultra concentrated. I do have Menards right down the road so I’ll check on pricing for their pool bleach. Thanks.

Where should I go from here? SLAM the pool? Lower the pH a bit before doing that?

Thanks for all the help!
 
The high CC levels point to some sort of unidentified contamination.

If the cause was ammonia, the CC would usually break down and not remain persistent.

The only thing that I know of that will create persistent CC levels at 8 ppm is sulfamic acid.

MPS will contribute to CC levels, but that usually diminishes over time and the levels will usually be lower unless there was a lot of MPS added.

Do you know for sure if sulfamic acid or MPS was added or not?

I would do a SLAM and see what the results are.

If possible get the UV going to help break down the CC levels.

Let’s see what results a SLAM creates and go from there.
 
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JamesW said:
The high CC levels point to some sort of unidentified contamination.

If the cause was ammonia, the CC would usually break down and not remain persistent.

The only thing that I know of that will create persistent CC levels at 8 ppm is sulfamic acid.

MPS will contribute to CC levels, but that usually diminishes over time and the levels will usually be lower unless there was a lot of MPS added.

Do you know for sure if sulfamic acid or MPS was added or not?

I would do a SLAM and see what the results are.

If possible get the UV going to help break down the CC levels.

Let’s see what results a SLAM creates and go from there.
Click to expand...
I can’t guarantee they didn’t use sulfamic acid or MPS in the past. But when I moved in, I drained the pool to 6” deep in the shallowest part and refilled it. I have not added any of those since refilling. When I moved in, the pool had a green tinge (but clear) that the owner and pool company said was “normal.” Likely from the iron. But I didn’t want that so wanted to start fresh and hence looked for help here as the pool company didn’t seemed concerned that the water was that green tinge.

Do I need to adjust the pH before Slamming? I just don’t want to add any more chemicals than the absolute minimum to eliminate any other confounding issues. Thanks.
 
www.troublefreepool.com

SLAM - Shock Level and Maintain

We’ve all had to deal with a green pool. Clear algae from your pool with a SLAM! Read here to use shock level and maintain to clear your pool.
www.troublefreepool.com www.troublefreepool.com

Read the article and follow it step by step without shortcuts.

  • Check and adjust the pH to between 7.2 and 7.5. The pH test isn’t reliable during a SLAM so adjust pH before you start. There’s no need to test pH again until your SLAM process is completed.
 
ajw22 said:
www.troublefreepool.com

SLAM - Shock Level and Maintain

We’ve all had to deal with a green pool. Clear algae from your pool with a SLAM! Read here to use shock level and maintain to clear your pool.
www.troublefreepool.com www.troublefreepool.com

Read the article and follow it step by step without shortcuts.

  • Check and adjust the pH to between 7.2 and 7.5. The pH test isn’t reliable during a SLAM so adjust pH before you start. There’s no need to test pH again until your SLAM process is completed.
Click to expand...
Sounds good. I’ll go get some Muriatic acid at Menards now. And then let the SLAMming commence. :)
 
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A SLAM will probably make all of the iron come out as stains.

You can try to remove any iron first or just SLAM and maybe deal with any iron stains later.

You should probably try to filter the water to remove iron before it is added to the pool.
 
i_intub8_u said:
I can’t guarantee they didn’t use sulfamic acid or MPS in the past. But when I moved in, I drained the pool to 6” deep in the shallowest part and refilled it. I have not added any of those since refilling. When I moved in, the pool had a green tinge (but clear) that the owner and pool company said was “normal.” Likely from the iron. But I didn’t want that so wanted to start fresh and hence looked for help here as the pool company didn’t seemed concerned that the water was that green tinge.

Do I need to adjust the pH before Slamming? I just don’t want to add any more chemicals than the absolute minimum to eliminate any other confounding issues. Thanks.
Click to expand...
I might do the FC and CC test again and make sure you didn’t get the results backwards.
 

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