Does water sample location matter???

Farmerswife96

Active member
Sep 25, 2016
41
Reidsville
So, on a whim I decided to get a water sample from the deepest part of the pool(on the very bottom) and test it because DH and kids complain of stinging eyes and here are the results.
pH 7.5
FC 2 (I expected this since all the family was in it yesterday)
CC .5
CYA 40
TA 50 (This is concerning)
CH 250-275 (other samples have shown CH at 375)
My question is whether to use these results or test everything again. I usually get a sample from arms length deep away from skimmer and jets. Doing weekly scrub down and vacuuming today.
Thanks again TFP😊😎
On 7/1, my FC was 2 so I added 1 gallon of 10% LC. Pucks are in floater tied near a jet.
Thoughts???
 

borjis

LifeTime Supporter
Aug 19, 2014
2,904
Pacific NW
It does matter.

I had noticed if I sample water from the shallow end, then the deep end, there is usually
a bit higher chlorine reading from the deep end.

It's best to get your sample from the same section of deep end, about 1 foot down from the surface.

Stinging eyes when you have shown a good ph and cc rating has me puzzled. if the ph was way
off or the cc was 2 or more I would expect eye irritation.
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
43,196
Tucson, AZ
TA and pH and CYA and CH should not vary with location in water.

FC could vary depending on organics and circulation.
 

Farmerswife96

Active member
Sep 25, 2016
41
Reidsville
It does matter.

I had noticed if I sample water from the shallow end, then the deep end, there is usually
a bit higher chlorine reading from the deep end.

It's best to get your sample from the same section of deep end, about 1 foot down from the surface.

Stinging eyes when you have shown a good ph and cc rating has me puzzled. if the ph was way
off or the cc was 2 or more I would expect eye irritation.
Yes, I normally get my sample from the deep end midway on the end side as far down as I can reach.
My CC since testing started with TF 100 hasn't been over .5. And haven't struggled with creeping up pH. But, I have had high levels of CH and stopped adding the calcium hypochlorite.
Should I worry about the lower alkalinity? I switched to the regular muriatic acid, had been using the less fumes version which I learned was less % acid. I think it lowered the alkalinity.
 

Farmerswife96

Active member
Sep 25, 2016
41
Reidsville
Okay, I tested everything again, same results on everything except I noticed something that I'm now curious about. When I put the drops in to get CC, I only use 1 drop and it turns from pink to clear, so I figured .5. However, I let it sit while doing other tests and the water turned back to a very light pink again. Is this normal? Or could my CC be higher? I test over white paper on a white towel on my kitchen table.
 

borjis

LifeTime Supporter
Aug 19, 2014
2,904
Pacific NW
It is normal for it to turn pink again when sitting still for awhile.... just get the test result immediately
after test drops are put in.... your're good to go!
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
43,196
Tucson, AZ
The FAS-DPD will always turn back to pink if you leave it sit. Just add drops to clear and you are done.
 

Lynnster52

Well-known member
Apr 29, 2018
46
Cos Cob CT
Burning eyes could signal PH test is off & actual reading might be lower than 7.5. What do you use to test the PH? Check exp date on the bottle if using drops. (mine is expired so on my way to Leslie's...) Good luck!
 

Farmerswife96

Active member
Sep 25, 2016
41
Reidsville
Burning eyes could signal PH test is off & actual reading might be lower than 7.5. What do you use to test the PH? Check exp date on the bottle if using drops. (mine is expired so on my way to Leslie's...) Good luck!
I'm using the R-0014 drops that came with my TF 100 test kit, exp 4/20. ��
Got me puzzled��
 

Lynnster52

Well-known member
Apr 29, 2018
46
Cos Cob CT
Okay, I tested everything again, same results on everything except I noticed something that I'm now curious about. When I put the drops in to get CC, I only use 1 drop and it turns from pink to clear, so I figured .5. However, I let it sit while doing other tests and the water turned back to a very light pink again. Is this normal? Or could my CC be higher? I test over white paper on a white towel on my kitchen table.
Very normal & you test as I do, including the white paper towel. So all good if one drop clears the pink. Result is read immediately, because waiting will always turn it back to pink! I have no explanation for that but was my first question when I switched over to this test method this year!
 

Poolzzz

Well-known member
Aug 14, 2017
373
Vancouver, BC
Regarding the FC test, it keeps changing back to pink because the CYA buffer keeps releasing FC in an effort to maintain chemical equilibrium. It'll do that until the CYA buffer has released all it's chlorine (assuming enough powder was used). It's an exponential decay function so will do this forever (although by the time forever happens the amount of chlorine being released would be infinitely small).

Theoretically this means the speed in which you do the test will affect the result, but in practice it doesn't matter because in the time it takes to do the test and show clear effectively all the FC has been measured. The remainder is less than the 0.5ppm of one drop even if you waited for infinity to remeasure.