CH test turns clear not blue

gonfishin

Gold Supporter
Jun 13, 2017
277
Rochester, MN
I know CH level doesn’t really matter for a vinyl pool, but with hard water, I like to keep an eye on all levels to prevent scaling in my SWCG and heat pump. Today I wanted to test CYA, TA, CH, and salt since I’ve neglected these tests for a couple of weeks and I’ve needed to add water.

The CH test was done with 10 ml sample.
10 drops R10, 3 drops R11 which turned pink.
8th drop of R12 turned clear.
9th drop no further change.

I ran the test twice with the same results. Reagents were purchased December 2018 from TFtestkits.

Call my CH 200 and ignore the clear or go after new reagents or something else?
 

gonfishin

Gold Supporter
Jun 13, 2017
277
Rochester, MN
Did you see anything that looked like blue particulates at the bottom of the test tube?
Matt, I don’t recall any during my afternoon test.

Result can be 'more or less blue'. If it is faint, the background around your vial may influence the resulting color.
I reran the test tonight, used the background light on the speed stir, and did it indoors. This time I got a very faint blue at the 7th drop, with the 8th drop not changing the color. I’ll use outdoor lighting combined with background as the explanation.

Thank you, Matt and Marty.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
15,765
Tucson, AZ
My guess is you are not adding enough R-0011L. The reagent is very viscous and doesn’t form complete drops very well. Typically the indicator just dribbles off the fitment in very small drop sizes. You can add an extra drop of the R-0011L to make the color contrast more distinct. It won’t affect the test result.

Also, tilt the bottle while capped and look at the reagent. If there’s a clump of solid material at the bottom of the bottle or a thick mass clinging to the side wall, then the reagent is compromised and needs to be discarded.
 
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gonfishin

Gold Supporter
Jun 13, 2017
277
Rochester, MN
Thanks, Matt.

I don't see any clumping or discoloration. I'll try to remember to add an extra drop when I run the test the next time.