CYA Differentials, Mine vs. Pool Stoe

[bxcrwlly]

Have been trying to get my CYA up to 70-75. Tested last week using my Taylor K2006. Dot disappeared around 50ppm. Before adding additional stabilizer, decided to take a water sample to pool store. They tested CYA at 100ppm. When performing my K2006 test, I wait for water temperature in sample bottle to equalize with room/outside temperature before completing test. I'm using a fresh reagent. I don't get why the wide span differential? So now, not sure whether to drain water or simply trust my K2006 reading and add stabilizer to bring up to 70-75ppm.

Thoughts/Ideas?

 

[Isaac-1]

What are your lighting condition, the test should be ran in sunlight with the sun to your back

 

[Bama Rambler]

Trust your own testing. The CYA test is the test the pool stores get wrong almost all the time. They get the most wildly incorrect readings sometimes. I've had them test tap water and say there was CYA in it. I've also had them test water I knew CYA was in and had them say there was zero.

Again, trust your own testing.

 

[Butterfly]

Always trust your own testing over the pool store.

Here's a link to extended testing instructions just to confirm your testing techniques.
extended-test-kit-directions-t25081.html

Once you confirm your techniques, have confidence in YOUR testing


ETA: Bama beat me

 

[bxcrwlly]

As always thanks for the feedback. Re Isaac-1's comments regarding lighting; I test outside under the lanai overhang with sun to my back. Are you suggesting to move into bright sunlight with sun to my back?

 

[jblizzle]

Try it and see if it makes a difference. I usually stand in the sun, but I would not think standing in the shade would matter much.