Can't Achieve Total Water Balance - Darn Chlorimines

[RADMO]

Hello, can you please help us figure out why we cannot eliminate our chlorimines.

We have a 20,000 gallon saltwater pool with aquapure 1400 SWG and fibergel coated surface.

The guy at Leslies pools recommended a non-chlorine shock with Fresh & Clear, and not to use a chlorine based shock in our salt pool, he said since we had plenty free chlorine.

Note: prior to our potassium monopersulfate shock this morning, last week we did add 10lbs of Calcium Chloride to raise the CH - I believe it was low from rain water and the fact we do not have plaster and do not use calcium based chlorine, our surface manufacture recommends the CH to be at around 300 range.

We turned our SWG off today and our reading BEFORE we shocked the pool today with 4lb bags of Fresh & Clear was:

Free Chlorine: 2.2

Total Chlorine: 3.4

Combined Chlorine: 1.2

PH: 7.5

ALK: 105

CYA: 67

CH: 220

Copper: 0.1

Iron: 0.0

Phosphates: 120

Salt: 3400

Temp: 70

Our reading AFTER we shocked the pool today is:

Free Chlorine: 3.88

Total Chlorine: 5.87

Combined Chlorine: 1.99

PH: 7.9

ALK: 98

CYA: 65

CH: 221

Copper: 0.1

Iron: 0.0

Phosphates: 120

Salt: 3400

Temp: 69

[chem geek]

Non-chlorine shock (potassium monopersulfate, MPS) will register as Combined Chlorine (CC) in test kits. If you use an accurate FAS-DPD chlorine test kit (such as the Taylor K-2006 kit or the TF-100 kit), then you can get an MPS interference remover with the K-2042.

However, all you really needed to do was to shock the pool with chlorinating liquid (or bleach) to 40% of the CYA level, so around 28 ppm and keep it there until you measure <= 1 ppm FC drop overnight and the CC measured <= 0.5 ppm. I would NOT trust the pool store measurements. Get your own good test kit instead.

[RADMO]

Non-chlorine shock (potassium monopersulfate, MPS) will register as Combined Chlorine (CC) in test kits. If you use an accurate FAS-DPD chlorine test kit (such as the Taylor K-2006 kit or the TF-100 kit), then you can get an MPS interference remover with the K-2042.

However, all you really needed to do was to shock the pool with chlorinating liquid (or bleach) to 40% of the CYA level, so around 28 ppm and keep it there until you measure <= 1 ppm FC drop overnight and the CC measured <= 0.5 ppm. I would NOT trust the pool store measurements. Get your own good test kit instead.

Thank you for replying. We purchased the LaMotte Qpro11 with the tablets. That is how we are getting our readings. Hope that is accurate. Sorry to be such a novice, we are trying to learn our pool but is much more complicated than we ever expected. We had to fire the pool guy for multiple no shows.

We are confused that MPS is reading as chlorine, perhaps they make a tablet to remove that as well? We have never performed a liquid chlorine shock,Is this ok for the fibregel coated pools?

What should the Total Chlorine read? How much do you think it will take for a 20,000 gallon pool?

Will we need to re-add more conditioner to bring our CYA level back up to 60 again after we use the liquid chlorine?

Should we turn the aquapure chlorine generator off while we are shocking the pool using liquid chlorine?

Thanks again for all your help here..

[chem geek]

You'll have to check with LaMotte to see if they have the interference remover or you can just wait since the MPS should be gone in a day or two assuming there are things to oxidize in the pool.

Yes, liquid chlorine at shock levels is fine for any type of pool. The key is that you have CYA in the water since that significantly moderates chlorine's strength. The CYA will not drop just because you shock the pool.

Yes, you can turn off the chlorine generator when you shock the pool. It doesn't need to be on and you'll want the chlorine level to drop after the shock. If the pH is higher than 7.3, I'd lower it first before adding the liquid chlorine. You can use The Pool Calculator to calculate dosages.

You can read the Pool School article Shock Your Pool for more info. When adding any concentrated chemical, especially acid or chlorine, to the pool, you can do so by pouring slowly over a return flow in the deep end with the pump running. Then, after you've added the chemical, lightly brush the side and bottom of the pool to ensure thorough mixing. Keep the pump running to mix the chlorine throughout the pool -- at least an hour.

If you want, you can just shock to 20 ppm FC and see how that goes. Note that your pH reading will be invalid and may read falsely too high when the FC is above 10 ppm. Also, your chlorine tester might not accurately read chlorine levels above 10 ppm if it is using a DPD test -- you might have to dilute the water sample to get an accurate reading.

[urpoolguru]

Chem Geek is giving good advice

[chem geek]

Better check your Nitrates too! Excessive levels will compound your problems with Chloramines.

How is that? Nitrates are a nutrient for algae and bacteria, just as with phosphates. How do higher nitrate levels affect chloramines? I don't see the chemistry in that except that continued chlorination that oxidizes ammonia and organics does produce some nitrate as a by-product.

[RADMO]

Better check your Nitrates too! Excessive levels will compound your problems with Chloramines.

How is that? Nitrates are a nutrient for algae and bacteria, just as with phosphates. How do higher nitrate levels affect chloramines? I don't see the chemistry in that except that continued chlorination that oxidizes ammonia and organics does produce some nitrate as a by-product.

Thanks folks!! - we have tested our phosphates, but is there a seperate test for nitrates? I just finished testing the pool water this morning after the MPS had a chance to settle - we have NOT had the chlorinator on, despite the mysterious increase in chlorine; here are this mornings current readings:

Free Chlorine: 3.62

Total Chlorine: 5.53

Combined Chlorine: 1.91

PH: 7.5

ALK: 103

CYA: 73

CH: 233

Copper: 0.1

Iron: 0.0

Phosphates: 120

Salt: 3400

Temp: 66

[RADMO]

Better check your Nitrates too! Excessive levels will compound your problems with Chloramines.

How is that? Nitrates are a nutrient for algae and bacteria, just as with phosphates. How do higher nitrate levels affect chloramines? I don't see the chemistry in that except that continued chlorination that oxidizes ammonia and organics does produce some nitrate as a by-product.

Thanks folks!! - we have tested our phosphates, but is there a seperate test for nitrates? I just finished testing the pool water this morning after the MPS had a chance to settle - we have NOT had the chlorinator on, despite the mysterious increase in chlorine; here are this mornings current readings:

Free Chlorine: 3.62

Total Chlorine: 5.53

Combined Chlorine: 1.91

PH: 7.5

ALK: 103

CYA: 73

CH: 233

Copper: 0.1

Iron: 0.0

Phosphates: 120

Salt: 3400

Temp: 66

Sorry to be such a pest.. but I think I may be missing a piece of the puzzle here. For the most part, I have been trying to keep the FC and TC close to the same number (between 2.0ppm and 3.0ppm) now that the TC was up to 5.87ppm after MPS shock, it took 2 days to lower to 5.53ppm.

I told my husband I want to raise the TC to 28.0ppm he saidd by his calculation we will not be down to 2.5ppm until around July??

Ok, he is telling me to hire another pool guy, I told him the pool guy never measured the water, just flirted alot - ok, no to the pool guy... but no to the 9 gallons of chlorine either.. any other suggestions here , I sure need help!

[urpoolguru]

After chwcking my texts Chem Geek is on the ball

[RADMO]

Our chlorine dropped another .03ppm today. When you shock the chlorine to 28ppm and the pool only loses .03ppm a day, does it take 100+ days to rid the pool of the 28ppm liquid chlorine? Just doesnt make sense how you can shock to 28ppm - what do you use to lower it back down to safe swimming range?? Just waiting for it to lower will take months on end, at the rate our pool loses chlorine.

[urpoolguru]

Our chlorine dropped another .03ppm today. When you shock the chlorine to 28ppm and the pool only loses .03ppm a day, does it take 100+ days to rid the pool of the 28ppm liquid chlorine? Just doesnt make sense how you can shock to 28ppm - what do you use to lower it back down to safe swimming range?? Just waiting for it to lower will take months on end, at the rate our pool loses chlorine.

Your local pool chemical supplier should have what you need or at least can get it. If my memory serves correct it is sodium thiosulfate (sp?).

[chem geek]

I told my husband I want to raise the TC to 28.0ppm he saidd by his calculation we will not be down to 2.5ppm until around July??

Is the pool exposed to sunlight? If so, the chlorine will drop over time -- possibly 20-25% per day. So 28 to 23 to 17 to 14, etc. And you could always dechlorinate to have it drop faster if you needed to. Anyway since you won't be shocking, you can just see if the combined chlorine goes away on its own.

[chem geek]

Zeolite can be used to remove Ammonia compounds in pools. This is a chemical free method and may resolve your issue quickly and easily. If your have a sand filter you can replace the sand with Zeolite. If not you could simply pour it into a pillow case tie it off and put it over your main drain. You should see a drop in your chloramines in a few days. Once you remove the Zeolite soak it a bucket of salt water for 24hrs rinse it with fresh water and it can be used over and over. Ammonia compounds bond with your chlorine forming chloramines. No ammonia no chloramines. Be sure to rinse the zeolite thoroughly before using it as it usually has some clay residue in it.

Regarding nitrates and chloramines...it is my understanding that when breaking down chloramines you are freeing the ammonia from the chlorine if the nitrate levels are excessively high you might get foaming.

If there is any Free Chlorine in the pool, then any ammonia in the pool will quickly (in seconds to one minute) combine with chlorine to form monochloramine and that will NOT be removed by zeolite. Zeolite removes ammonia, but NOT monochloramine. So the claims about no ammonia no chloramines (that some zeolite manufacturers make) are misleading at best. They do not tell you that ammonia combines with chlorine in seconds to form monochloramine long before any ammonia gets any chance to circulate to the Zeolite filter.

As for breaking down chloramines, you do not release ammonia but instead chlorine oxidizes monochloramine to dichloramine and nitrogen trichloride that further get oxidized to produce mostly nitrogen gas. So the result is not ammonia. There is a small amount of nitrates produced as well.

As for high nitrate levels producing foaming, I've never heard of that. I know that low calcium hardness (CH) levels below 120 ppm can have more foaming in the water.

[poolaidman]

Hello, can you please help us figure out why we cannot eliminate our chlorimines.

We have a 20,000 gallon saltwater pool with aquapure 1400 SWG and fibergel coated surface.

The guy at Leslies pools recommended a non-chlorine shock with Fresh & Clear, and not to use a chlorine based shock in our salt pool, he said since we had plenty free chlorine.

Note: prior to our potassium monopersulfate shock this morning, last week we did add 10lbs of Calcium Chloride to raise the CH - I believe it was low from rain water and the fact we do not have plaster and do not use calcium based chlorine, our surface manufacture recommends the CH to be at around 300 range.

We turned our SWG off today and our reading BEFORE we shocked the pool today with 4lb bags of Fresh & Clear was:

Free Chlorine: 2.2

Total Chlorine: 3.4

Combined Chlorine: 1.2

PH: 7.5

ALK: 105

CYA: 67

CH: 220

Copper: 0.1

Iron: 0.0

Phosphates: 120

Salt: 3400

Temp: 70

Our reading AFTER we shocked the pool today is:

Free Chlorine: 3.88

Total Chlorine: 5.87

Combined Chlorine: 1.99

PH: 7.9

ALK: 98

CYA: 65

CH: 221

Copper: 0.1

Iron: 0.0

Phosphates: 120

Salt: 3400

Temp: 69

the pool needs to be shocked to kill the chloramines. Use liquid chlorine (its ok to use) add 2 gallons to properly shock your pool.

[Richard320]

Pardon my ignorance, but how do you get such precise numbers?

Free Chlorine: 3.88

Total Chlorine: 5.87

I'm wondering if some of your problems couldn't be caused by testing error?

[chem geek]

I initially thought the same thing, but Radmo said he was using "LaMotte Qpro11 with the tablets" which is an electronic tester. I doubt it is as accurate as implied by the 0.01 precision (readout). I would verify with a FAS-DPD drop-based test accurate to within 0.2 ppm and not worry if the CC is anything less than 0.5 ppm.

[RADMO]

Pardon my ignorance, but how do you get such precise numbers?

Free Chlorine: 3.88

Total Chlorine: 5.87

I'm wondering if some of your problems couldn't be caused by testing error?

Hi guys, back at the pool again this morning. I did NOT run the filter last night, and of course I have had the salt chlorinator off now for 3 days.

Today here is our readings. (did i mention the water is sparkling clean?)

20,000 gallon (10ft in deep end) and raised spa rocked in with spillover to kidney shaped outdoor pool in southern calif.

White Fibregel coat over plaster.

Jandy aqaulink PDA with 400btu Maxitherm heater, inteliflo pump

Free Chlorine: 2.86

Total Chlorine: 3.57

Combined Chlorine: .71

PH: 7.6

ALK: 103

CYA: 67

CH: 210

Copper: 0.1

Iron: 0.0

Phosphates: 120

Salt: 3400

Temp: 66

What is the highest chlorine level we can have and still use the spa. I am wondering how many days it will be without use while we await the shock level to drop from 28ppm back down to 2.5ppm. How does one go about reducing the chlorine once it is up that high? No doubt we should leave the chlorinator OFF during that process? The fibregel company says our CH should be 300-350 , perhaps we can use a CALHYPO shock and get our chlorine shocked and calcium raised at the same time?

Thanks again for all your help!

Linda

[chem geek]

It's rather unusual for a saltwater chlorine generator (SWG) pool to have combined chlorine as high as you are seeing, especially for an extended period of time and especially with an outdoor pool exposed to sunlight (with low bather load, as with most residential pools). Since this could be some sort of test error, you could try a bucket experiment where you take a large bucket or basin of pool water and shock it with chlorine, wait a while (a day) and see if the CC drops (you use your tester before the shock to get a baseline of the water in the bucket/basin). Shocking to around 25 ppm FC would be 1/3rd teaspoon of 6% Clorox regular unscented bleach per gallon -- it doesn't have to be precise -- you just want to see if shocking will make any difference.

Since your pool is clear and you don't apparently smell the combined chlorine, it's probably either not real (i.e. test error) or not a problem -- could be something innocuous like chlorourea, though I'm surprised the SWG isn't getting rid of it.

You could also take a pool water sample to a pool store for a comparison measurement, though many pool stores don't test properly (but at least it will be another datapoint). If you had a FAS-DPD chlorine test for comparison, that would be best.

Shocking the pool to an FC that is around 40% of the CYA level has the same amount of active chlorine (hypochlorous acid) as 0.6 ppm FC with no CYA so less than found in most indoor pools. Nevertheless, in a spa, I would expect the smell of chlorine to be noticeable. Usually in a spa, most people don't notice the chlorine when it gets to around 1 ppm FC with 30 ppm CYA or its equivalent so that would be around 2.2 ppm FC in your case. If you've ever been to a commercial/public spa, it will smell quite a bit less than that since they are usually at 2-5 ppm FC with no CYA.

[RADMO]

woohoo ChemGeek - much apreciated, we are using the LaMotte Color Q pro 11 (tablet system pretty straight forward use) and the guy at La Motte said to use MPS Out” reagent 6910-E to nutrilize the MPS we shocked with last week (we are awaiting delivery) but the Calcium Chloride nutrilizer I am still waiting to hear back from them (we added several pounds of that last week to raise our CH) - La Motte is closed today for good friday so i will have to check with him again on Monday. I am going to try the bucket test for the CC and also haul the water off to pool store for double-dog test comparisons. Thanks again!! Linda

[RADMO]

woohoo ChemGeek - much apreciated, we are using the LaMotte Color Q pro 11 (tablet system pretty straight forward use) and the guy at La Motte said to use MPS Out” reagent 6910-E to nutrilize the MPS we shocked with last week (we are awaiting delivery) but the Calcium Chloride nutrilizer I am still waiting to hear back from them (we added several pounds of that last week to raise our CH) - La Motte is closed today for good friday so i will have to check with him again on Monday. I am going to try the bucket test for the CC and also haul the water off to pool store for double-dog test comparisons. Thanks again!! Linda

I ran the SWG last night and now Testing water this morning, our CC is lowering , we are at FC=357 and TC=379 and I am wondering if it isnt in fact the by-product of the Calcium Chloride that caused false readings of the CC. Our CH is now at 279 and we have not added any more Calcium Chloride since Monday, yet the CH reading is creeping up each day while the Combined Chlorine reading is creeping down...

However, I did notice the PH is up from 7.5 to around 7.8 - perhaps a splash of muriatic acid is due?

I sware, i told my husband even though our kids are now grown teens, getting a house with a pool is like having 3 new toddlers here all over again!

Linda

[chem geek]

So it does sound like the CC reading (TC-FC) was either not real or was getting handled over time on its own, which is what keeping an FC in the pool does anyway -- oxidation of CC is happening continuously and all that shocking does is to accelerate the process.

Normally the Calcium Hardness (CH) level does not interfere with the chlorine test, but I don't know enough about the specifics of the LaMotte test to know if it's a problem for their test -- I doubt it, but they can tell you for sure. As for the CH creeping up, that has got to be test error unless you've got some slowly dissolving calcium chloride pellets in the water -- usually they dissolve fairly quickly.

The pH in a saltwater chlorine generator (SWG) pool will tend to rise over time unless you keep the Total Alkalinity (TA) lower (yours is at around 100 ppm which is on the high side -- it could be at 70 ppm). See Water Balance for SWGs for more info. As for lowering the pH with Muriatic Acid, you can use The Pool Calculator to figure out dosing.

[RADMO]

I tried the bucket shock with chlorine and the water shocked up just fine, reading 25ppm, it is now at around 5.2 (i left it out in the sun) but it has very little to no CC.

Meanwhile, I hauled our pool water off to the local Leslies, showed him the SWG printout from POOLSCHOOL and basically they had no choice but then to agree with the POOLSCHOOL - they tested my water and said it was in near "perfect" condition.

If all customers used this forum to correct their pool water - then brought pool water in that clean - they would be out of biz!

They showed my FC and TC to be at 3.1

My PH at 7.6 and AKL at 100 with CYA at 50 (instead of my upper 60 reading) and CH at 250 (instead of my 233 reading) - i am going to call LaMotte on Monday to see if they have some tricks to their test kits....

Meanwhile, Leslies suggestion, a cup of Muriatic acid overnight and enjoy the pool!

Thanks again to everyone for your help this round.. I am sure my pool (aka wicked stepchild) will have a need to return to this forum in the near distant future.

Allbest,

Linda