Testing city water with pool test kit...

PieterS

Bronze Supporter
Jul 1, 2020
100
Minneapolis, MN
OK - so not quite on topic - but having recently installed a whole-house carbon filter, and now wondering if my 10-year-old water softener resin might need replacing - is the TF100 or K2006C test kit useful in testing your household tap water?

Specifically:
1) is the calcium hardness test equivalent/useful for testing the hardness of city water? Does it correlate to 'grains' of hardness?
2) Is the CL test sensitive enough to test the amt of chlorine typically added to city water for sanitization? And therefore I could measure it before/after the water filter.

Thanks!
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
44,347
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Yes and yes.
GPG = ppm/17.118

Be sure to do the CC portion of the FAS-DPD, some water systems use chloramines.
 
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PieterS

Bronze Supporter
Jul 1, 2020
100
Minneapolis, MN
Thanks for the quick response @mknauss. I'll give this a shot tonight. I did check with the city already and they claim they use chlorine, but I'll do the CC portion regardless. Another good use of this awesome test kit!
 

PieterS

Bronze Supporter
Jul 1, 2020
100
Minneapolis, MN
Gave this a shot - seemed to work. Trying to figure out of it's close to time to replace my water softener resin bed. Just before regenerating, the calcium hardness was around 160 ppm (hard to tell the red to blue/purple transition!) so around 9 gpg - the incoming water tested closer to 200 ppm (almost 12 gpg). AFTER regenerating - the calcium hardness hardly registered.

The chlorine test (to check on the whole house carbon filter) was a bit confusing at first. Taken from the outside spigot (hard, non-filtered water) I still registered NO chlorine. Thinking maybe I didn't flush enough water out first, I did recall I have a drain spigot inside that is before the filter/softener - tested that, and I registered between 0.4 and 0.6 PPM. Still maybe a bit less than what I'd expect in city water? But I don't know what I should expect... The AFTER filter water didn't register ANY chlorine (didn't turn any shade of pink after adding powder).
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
44,347
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Sounds about right. Metals in the water can interfere with the CH test. There is a protocol for that in the Extended Test directions in Pool School.

That amount of FC in tap water sounds about right. Can be higher (EPA allows up to 4 ppm FC) but typically it has fallen by the time it gets to you.
 

Oly

Gold Supporter
Jun 28, 2017
2,339
Fresno, CA
Pool Size
27000
Using a Speed Stir magnetic stirring device will make the titration test color change end point easier to determine.
 
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ccbill

Well-known member
Jul 23, 2021
140
Atascadero, Ca
Pool Size
23000
Surface
Plaster
Chlorine
Liquid Chlorine
I used my kit to test my house water and the results compared very well with the water company's annual report.
 
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PieterS

Bronze Supporter
Jul 1, 2020
100
Minneapolis, MN
Using a Speed Stir magnetic stirring device will make the titration test color change end point easier to determine.
Yeah, I've resisted so far but this might push me over the edge! Dropping with one hand, swirling with the other, and trying to get a good angle for color change wasn't easy :)
 

Oly

Gold Supporter
Jun 28, 2017
2,339
Fresno, CA
Pool Size
27000
I only recently bought one after years of perfecting the two handed swirl and dropper method. The bottom illumination of the sample vial was an unexpected surprise and makes sampling after dark a snap. Small and compact too, well designed. :goodjob:
 
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