Indoor, in ground pool high combined chlorine

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I added 2 quarts of muriatic acid which brought the pH down to 7.2.

I waited 30 mins with the pump running and then added my SLAM liquid chlorine. The target level according to pool math is a FC level of 20. I added a little over 4 gallons of 7.17% chlorine bleach (plain, unscented).

I waited 30 mins and took a pool water sample at elbow depth. My test kit results:

FC: 3ppm
CC: 6.5ppm
TC: 9.5ppm

Did it really use up all that liquid chlorine that fast? I suppose that’s what the SLAM is doing - reacting with the CCs to clear them, right?

I will say that when adding the R-0871 reagent, it went totally clear after 6 drops (3ppm FC). But then as I was getting the R-0003 reagent out, it turned a slight pink again. Is that normal? The tips sheet says you have to be quick about this test or it will turn pink again if left sitting on the counter. But it was probably only 20 seconds or so. I have the smart stick and stirrer so it’s getting mixed well.

Should I put a FC of 3 into pool math and add another 3-4 gallons like it says? Or am I doing something wrong? Thanks!
 
Combined chlorine compounds are usually based on nitrogen like in ammonia or carbon like in organic molecules.

Nitrogen products can come from nitrogen containing compounds such as urine, sweat, and skin cells or from ammonia or other nitrogen containing compounds.

Disinfection by-products (DBPs) are formed when disinfectants like chlorine interact with NOM (Natural Organic Matter) in water.

Two of the most common types of DBPs found in chlorinated water are trihalomethanes (THMs) and haloacetic acids (HAAs).

Trihalomethanes and haloacetic acids are the largest groups of water disinfection by-products by weight, making up about 50% to 75% of total halogenated disinfection by-products

Haloacetic acids (HAAs) can be caused by humic acids, which can also cause the water to have a brownish color.

Dissolved Organic Matter (DOM) or NOM (Natural Organic Matter) are compounds created by decaying leaves, vegetation etc.

For your pool based on well water, the CC is probably going to be haloacetic acid.

The chlorine needs to oxidize the carbon to elemental carbon or to carbon dioxide.

Compounds like MPS, ozone, hydrogen peroxide etc. are not CCs, but they test as CCs because they oxidize the iodide in the reagent into iodine, which then reacts with the DPD reagent.
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Simple plants, such as algae, create chemicals like glucose from carbon dioxide and water.

Using light, the carbon in carbon dioxide oxidizes the oxide into oxygen.

6CO2 + 6H2O --> C6H12O6 + 6O2

Carbon dioxide + water--> glucose + oxygen.

This is how plants make oxygen and store energy in sugars.

The carbon in carbon dioxide is in the +4 state.

1701226650524.png

The carbon in glucose is 4 at 0, 1 at -1 and 1 at +1.

1701226590851.png

The carbon is "reduced", which is the opposite of oxidized.

Reduced just means that the oxidation state is lower or reduced because the atom gained electrons which are negatively charged.

When chlorine oxidizes the carbon in glucose back to a +4 oxidation state, it reverts back to carbon dioxide.

This is a similar process to an animal using oxygen to burn sugars to release energy and exhale carbon dioxide.

So, chlorine reacting with algae is mostly an oxidation reaction and not a combination.

Algae is mostly converted back into carbon dioxide and water.

Chlorine can combine with carbon compounds, such as methane (CH4) by replacing the hydrogen ions.

Carbon in methane is in the -4 oxidation state.

Algae mostly does not create CCs.

CCs are mostly created by compounds like ammonia where the nitrogen is in the -3 state.

For ammonia, you get combination and oxidation.

So, the CCs eventually go away, especially in sunlight where UV photons knock loose electrons from the nitrogen and make it easier for the chlorine to take them.

Active chlorine is +1, so it bonds with more negatively charged atoms, like nitrogen in the -3 (ammonia) state or carbon in the -3 (acetic acid) or -4 (methane) state.

The carbon in algae has a zero net charge.

So, the reaction of chlorine with algae is mostly oxidation and not combination.

For natural organic matter, the carbon is in a state that is more likely to combine with chlorine creating CCs.
 
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JamesW said:
Combined chlorine compounds are usually based on nitrogen like in ammonia or carbon like in organic molecules.

Nitrogen products can come from nitrogen containing compounds such as urine, sweat, and skin cells or from ammonia or other nitrogen containing compounds.

Disinfection by-products (DBPs) are formed when disinfectants like chlorine interact with NOM (Natural Organic Matter) in water.

Two of the most common types of DBPs found in chlorinated water are trihalomethanes (THMs) and haloacetic acids (HAAs).

Trihalomethanes and haloacetic acids are the largest groups of water disinfection by-products by weight, making up about 50% to 75% of total halogenated disinfection by-products

Haloacetic acids (HAAs) can be caused by humic acids, which can also cause the water to have a brownish color.

Dissolved Organic Matter (DOM) or NOM (Natural Organic Matter) are compounds created by decaying leaves, vegetation etc.

For your pool based on well water, the CC is probably going to be haloacetic acid.

The chlorine needs to oxidize the carbon to elemental carbon or to carbon dioxide.

Compounds like MPS, ozone, hydrogen peroxide etc. are not CCs, but they test as CCs because they oxidize the iodide in the reagent into iodine, which then reacts with the DPD reagent.
_______________________________________________________________________________________

View attachment 542480

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View attachment 542477

_______________________________________________________________________________________

View attachment 542478


_______________________________________________________________________________________

View attachment 542479


_______________________________________________________________________________________

Simple plants, such as algae, create chemicals like glucose from carbon dioxide and water.

Using light, the carbon in carbon dioxide oxidizes the oxide into oxygen.

6CO2 + 6H2O --> C6H12O6 + 6O2

Carbon dioxide + water--> glucose + oxygen.

This is how plants make oxygen and store energy in sugars.

The carbon in carbon dioxide is in the +4 state.

View attachment 542486

The carbon in glucose is 4 at 0, 1 at -1 and 1 at +1.

View attachment 542485

The carbon is "reduced", which is the opposite of oxidized.

Reduced just means that the oxidation state is lower or reduced because the atom gained electrons which are negatively charged.

When chlorine oxidizes the carbon in glucose back to a +4 oxidation state, it reverts back to carbon dioxide.

This is a similar process to an animal using oxygen to burn sugars to release energy and exhale carbon dioxide.

So, chlorine reacting with algae is mostly an oxidation reaction and not a combination.

Algae is mostly converted back into carbon dioxide and water.

Chlorine can combine with carbon compounds, such as methane (CH4) by replacing the hydrogen ions.

Carbon in methane is in the -4 oxidation state.

Algae mostly does not create CCs.

CCs are mostly created by compounds like ammonia where the nitrogen is in the -3 state.

For ammonia, you get combination and oxidation.

So, the CCs eventually go away, especially in sunlight where UV photons knock loose electrons from the nitrogen and make it easier for the chlorine to take them.

Active chlorine is +1, so it bonds with more negatively charged atoms, like nitrogen in the -3 (ammonia) state or carbon in the -3 (acetic acid) or -4 (methane) state.

The carbon in algae has a zero net charge.

So, the reaction of chlorine with algae is mostly oxidation and not combination.

For natural organic matter, the carbon is in a state that is more likely to combine with chlorine creating CCs.
Click to expand...
Reminds me of my biochem or organic chemistry classes back in medical school, haha. I’m off to buy more bleach. Used almost the whole 9 gallons I bought for the SLAM the first night.
 
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You might want to have your water tested for Dissolved Organic Matter (DOM) or NOM (Natural Organic Matter), which are compounds created by decaying leaves, vegetation etc. that produce products like methane and other reduced carbon molecules.

You might want to get some sort of treatment for the water to remove products like iron and compounds that are caused by decomposition of organics like vegetation.

The Impact of Dissolved Organic Matter Composition on the Formation of Disinfection Byproducts in Groundwater | WRI

Naturally occurring dissolved organic matter (DOM) poses a risk to human health when it reacts with disinfectants (e.g., chlorine) to form harmful disinfection by-products (DBPs) during drinking water treatment. Past research has shown that the DBP formation potential of DOM in surface waters...
www.wri.wisc.edu www.wri.wisc.edu


 

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JamesW said:
You might want to have your water tested for Dissolved Organic Matter (DOM) or NOM (Natural Organic Matter), which are compounds created by decaying leaves, vegetation etc. that produce products like methane and other reduced carbon molecules.

You might want to get some sort of treatment for the water to remove products like iron and compounds that are caused by decomposition of organics like vegetation.

The Impact of Dissolved Organic Matter Composition on the Formation of Disinfection Byproducts in Groundwater | WRI

Naturally occurring dissolved organic matter (DOM) poses a risk to human health when it reacts with disinfectants (e.g., chlorine) to form harmful disinfection by-products (DBPs) during drinking water treatment. Past research has shown that the DBP formation potential of DOM in surface waters...
www.wri.wisc.edu www.wri.wisc.edu


Click to expand...
Ok I’ll look into that. What kind of treatment would be available to use?

I have another iron filter available to me I might plumb into the system to filter before the sprinkler and pool water fill.
 
i_intub8_u said:
What kind of treatment would be available to use?
Click to expand...
I am not familiar with treating that type of issue.

Find a local water treatment company that can test the water and provide options for filtration and remediation based on the test results.

There are various filters that can prefilter and then you can go as far as RO reverse osmosis to get cleaner water.

It partly depends on what the tests show and how much you want to spend on treatment equipment.

Is this being used as drinking water?
 
JamesW said:
I am not familiar with treating that type of issue.

Find a local water treatment company that can test the water and provide options for filtration and remediation based on the test results.

There are various filters that can prefilter and then you can go as far as RO reverse osmosis to get cleaner water.

It partly depends on what the tests show and how much you want to spend on treatment equipment.

Is this being used as drinking water?
Click to expand...
Ok. Yes it is being used for drinking water. The well test when we moved in received the ok from the water company. But it was just a standard test. I’ll have to do more intense/specific water testing. Thanks.
 
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Does the water smell and taste ok?

Well water can be subject to whatever might seep into the ground water, which might be anything from metals, pesticides, oil, fertilizer, fuel (like gasoline), decayed vegetation etc.

You can also check with local, city and state government resources for information about testing and remediation options.

Environmental Protection | Wisconsin DNR

dnr.wisconsin.gov dnr.wisconsin.gov

www.epa.gov

EPA in Wisconsin | US EPA

Web area for news and information about EPA's efforts in Wisconsin and WI environmental conditions.
www.epa.gov www.epa.gov

Local Universities will often have resources available like testing and advice.

If you are near any type of farm, forest, swamp, industrial site etc. that might help identify what is in the water.
 
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The CC levels could indicate that the water is contaminated and maybe unsafe to drink.

There are many cases where water has been contaminated and caused health issues for people who drank or were otherwise exposed to the water.

I do not know if your situation is serious, but I would want a full analysis by a qualified testing lab to look for anything of concern.

In any case, I would recommend some sort of treatment for the non drinking water and probably RO for drinking water.

Camp Lejeune water contamination - Wikipedia

en.wikipedia.org en.wikipedia.org

en.wikipedia.org

Red Hill water crisis - Wikipedia

en.wikipedia.org en.wikipedia.org
 
Hydrocarbons like methane, octane, propane etc. consist of carbon in the -2, -3 or -4 state with hydrogen in the +1 state connected to the carbon atoms.

Chlorine is +1 and it can substitute for the +1 hydrogen and form a chlorinated hydrocarbon.

These tend to persist longer than simple nitrogen molecules like ammonia or chloramine.



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When raising fc to slam level and adding chlorine did the water color change (get more green or brownish)?
Got any polyfill on hand to deploy incase it does? You can sacrifice an old pillow or stuffed animal.
 
No it hasn’t changed to green or brown. On 24h of SLAM so far. My last reading was a FC of 2.5 and a CC of 7.5. I’ve used almost 16 gallons of 7.15% bleach so far. Might be making progress, but it seems to be slow. Thoughts?
 
JamesW said:
The CC levels could indicate that the water is contaminated and maybe unsafe to drink.

There are many cases where water has been contaminated and caused health issues for people who drank or were otherwise exposed to the water.

I do not know if your situation is serious, but I would want a full analysis by a qualified testing lab to look for anything of concern.

In any case, I would recommend some sort of treatment for the non drinking water and probably RO for drinking water.

Camp Lejeune water contamination - Wikipedia

en.wikipedia.org en.wikipedia.org

en.wikipedia.org

Red Hill water crisis - Wikipedia

en.wikipedia.org en.wikipedia.org
Click to expand...
Yes I’m going to get the water checked out for sure.
 
i_intub8_u said:
No it hasn’t changed to green or brown. On 24h of SLAM so far. My last reading was a FC of 2.5 and a CC of 7.5. I’ve used almost 16 gallons of 7.15% bleach so far. Might be making progress, but it seems to be slow. Thoughts?
Click to expand...
You should find better chlorine. Try a pool store, Walmart, etc for 10% or 12.5%
 
Bperry said:
You should find better chlorine. Try a pool store, Walmart, etc for 10% or 12.5%
Click to expand...
Ok. Walmart by me doesn’t have anything other than the 7%. Menards only has 2 gallons according to their online store (seasonal item). Fleet Farm has 12.5% 4 gallons for $16.99. I’ll call the pool stores tomorrow and see their prices.
 
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