Allright, TPF alumni changing pool water in real time

[SPP]

Hi Gang,

I promise to bring closure to my post by posting the after 50% water change Test Result.
I actually would expect the Chloride level to be lower than 556 PPM because initially it was 757 PPM.
If I changed my water by 50%, I should be getting 378 PPM and not 556 :grrrr:
The new water supposedly mountain water, does mountain water contain Chloride ?

True to what ChemGeek said, I should have send the "new" water for testing too........
Anyway some progress were made as per test but some actually went up in value

Turbidity improved from 1.68 to 1.32 ( I hope my staff uses a clean bottle. I was hoping better than 1.32, even though I totally have no reference how beautiful water clarity 1 NTU is.......... )

REDUCED - Color was 13.5 , now 11.5
REDUCED - Ammonia was 0.071 , now 0.048
REDUCED - Fluoride was 1.32, now 0.354
REDUCED - NO3 ( Nitrate ) was 5.54 , now 4.26
REDUCED - NO2 ( Nitrate ???? ) was 0.064 , now 0.031
REDUCED - Na ( Natrium ?? ) was 72.65 , now 57.62
REDUCED - TDS was 2070 , now 1215

INCREASED
The Iron was <0.01 now it is 0.083. So I think ChemGeek was accurate to suspect my new water has more iron than my old water based on the brownish color during super chlorination.............Dang you are GOOD my man !!! I should call you ChemGOD instead
Can I be getting iron from the rust of the steel water truck's tank ?

INCREASED
SO4 (Sulfate ) was 49.89 , now 83.54 .......me no understand this.

INCREASED - How Come ?????
CaCO3 ......was 136, now 186....

ChemGeek need to explain what all this means, me chemistry dummy

[attachment=0:3mu5qp1v]Water Test Result-After water change.jpg[/attachment:3mu5qp1v]

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[SPP]

I just read this while looking for NTU ( water clarity ) reference

http://www.en2solutions.net/Controlling ... 0Pools.pdf

Page 3 wrote :
" The National Sanitation Foundation (NSF) and the American Water Works
Association (AWWA) recommends that recreational water turbidity should be
maintained between 0.2 - 0.5 NTU, but should not exceed 0.5 NTU. However, for
short times during peak bather loading, this should not exceed 1.0 NTU and the
pool filtration system should be capable of returning the water to 0.5 NTU's within
6 hours following this peak use.
The American National Standard and NSF Internal Standard also use turbidity
measurement to test the performance of pool filters (ANSI/NSF 50 - 1992)"

Wow, I can only achieve this IF my pool is an indoor one.........
No way my city's ambient airborne dust will allow an outdoor pool to be under 1 NTU, let alone 0.5......yikes !!!
I am wondering NASA famous training pool.......what NTU is that ? Look so awesome !!!

sad.
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[chem geek]

I actually would expect the Chloride level to be lower than 556 PPM because initially it was 757 PPM.
If I changed my water by 50%, I should be getting 378 PPM and not 556 :grrrr:
The new water supposedly mountain water, does mountain water contain Chloride ?

Normally mountain water would be low in sodium chloride (salt), but a 50% water change having the chloride drop from 757 to 556 implies a fill water chloride level of 355 ppm. What is strange, however, is that the water report you showed doesn't appear to have proper charge balance. The TDS of 1215 ppm implies other substances, but the Total Hardness (sum of calcium and magnesium) is only 186.1 ppm and sodium is only 57.62 ppm. So unless there is a lot of potassium or lithium, then there's something wrong with the water report. Charges should balance on a molar basis (looking at species with any significant concentration):

556/35.453 + 2*83.54/96.06 + 4.26/62.00 = 17.49
Chloride + Sulfate + Nitrate

57.62/22.99 + 2*186.1/100.09 + ? + ? = 6.22 + ?
Sodium + 2*(Calcium + Magnesium) + Potassium + Lithium

So 11.27 moles/liter missing. If this is Potassium, then that would be 11.27*39.10 = 441 ppm

TDS from listed substances:
556 + 4.26 + 57.62 + 83.54 + 186.1* = 887
*Total Hardness as CaCO₃
but TDS was reported as 1215 so 328 ppm "missing" (actually more since calcium and magnesium have lower molecular weight than calcium carbonate units)

So maybe, in fact, there is potassium (K) in the water that they are not testing or listing.

Turbidity improved from 1.68 to 1.32 ( I hope my staff uses a clean bottle. I was hoping better than 1.32, even though I totally have no reference how beautiful water clarity 1 NTU is.......... )

The fill water could have some turbidity, but using the Slime Bag should help with that. The recommendations you quoted for clarity are not for swimming pools, but for drinking water. The quote you gave about 0.5 to 1.0 NTU as an NSF standard is not correct. NSF Standard 50 just requires filters to reduce 45 +/- 10 NTU by 70% after 5 passes (so down to 13.5 NTU or lower). See this link regarding turbidity in drinking water and note that though 0.1 NTU is an ideal goal, that in practice it is not achieved and that slow sand or DE filtration may result in a 95% standard of 1.0 NTU and no sample more than 3.0 NTU. The World Health Organization (WHO) does does list 0.5 NTU as a goal for disinfection (removal of some oocysts), but is generally only achieved with coagulation in addition to filtration. For natural waters, Health Canada recommends 50 NTU or less. You could probably get below 1 NTU if you didn't use your pool at all, but it's not practical with bather load constantly introducing dead skin cells and dirt increasing water turbidity.

REDUCED - NO2 ( Nitrate ???? ) was 0.064 , now 0.031
REDUCED - Na ( Natrium ?? ) was 72.65 , now 57.62

NO₂ is nitrite. Chlorine will convert this to nitrate. Na is sodium.

INCREASED
The Iron was <0.01 now it is 0.083. So I think ChemGeek was accurate to suspect my new water has more iron than my old water based on the brownish color during super chlorination.............Dang you are GOOD my man !!! I should call you ChemGOD instead
Can I be getting iron from the rust of the steel water truck's tank ?

So the fill water apparently has around 0.16 ppm iron which is not extraordinarily high, though apparently enough to cause significant coloring when chlorine is added. I'm a bit surprised as I would have expected even higher iron levels given what you normally see when chlorine is added and what gets filtered out by the Slime Bag.

INCREASED
SO4 (Sulfate ) was 49.89 , now 83.54 .......me no understand this.

This doesn't make sense to me either. Though there can clearly be sulfate in the fill water, I don't see how the sulfate level would have gone down in the pool water. Maybe your first water source (fill water) was lower in sulfate than this latest fill water, though presumably they are coming from the same source.

INCREASED - How Come ?????
CaCO3 ......was 136, now 186....

This also doesn't make sense unless you 1) lowered your calcium level in your pool by filtering out calcium carbonate, but your level didn't seem to be saturated (unless your Total Alkalinity was very, very high) or 2) this newer fill water may have more Total Hardness than your original fill water.

Does your tile pool have grout in between the tile? It sure looks like it does. Grout is likely to have calcium carbonate in it so why is it that you are not saturating the water with calcium carbonate by increasing Calcium Hardness (CH) to around 300 ppm or so, assuming your Total Alkalinity (TA) is something like 80 ppm or so?

 

[SPP]

Hi Chem,

Many many thanks.
The water lab belongs to a reputable University near my home, as to how accurate they are, I think its how good and calibrated their instruments are or if some test chemicals are not expired yet

I know when I send in the water, it has approx 2.5 PPM chlorine and it get so low in their test ( same as first test ), do you think they idle my water ini open air ( or sunlight ) for a long time ? Test result always 1 week being fastest after I submit the water, perhaps many people also doing test or they are busy perhaps.

01. I have not test my TA for a long time, its been stable so me never bother.
02. Yes, my pool has grouts
03. Perhaps I should send water to another lab, however between the water test after water change of 50%, city water been added to the pool at approx 400 liters a day ( some dumb leak ) and at least 50 or so divers & their gears have contaminated my pool.

Again many thanks Chem. I will never able to analyze this without you.

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