TF Test Kits standard solution

[jimbethesda]

I’m so excited for my new pool (we haven’t even broken ground yet) that I ordered my TF-100 test kit!

I bought the standard solution sampler to practice with. The only one I get the same result as expected was for CYA. Here’s what I got:

PH: 7.5 (sample bottle says 7.2)
TA: 80 (sample says 100)
CH: 150 (sample says 200)
CYA: 50 (sample says 50)

Should I practice more, or are these samples off?

 

[JoyfulNoise]

For CH the titration ends when the water sample reaches its final blue color NOT when it transitions from purple to blue. That can often be a 2-3 drop difference. TA is similar, the test stops when you’ve reached the final shade of red. That’s about a 1-2 drop difference.

pH is kind of hard standard to make in my opinion. That one’s not so important in my opinion.

 

[jimbethesda]

Ok, thanks. I didn’t notice any color change after the values I stated, but maybe I didn’t look closely enough. I also did it inside.

 

[Richard320]

For the pH, try the test again using only 4 drops of reagent and see if the color is easier to discern that way. Also make sure the background is white or neutral. I have the best luck holding it at arm's length and squinting so things get blurry.

 

[JoyfulNoise]

I would also suggest you do the tests outdoor in bright, indirect lighting. I personally prefer that and get the best color determination when I do.

 

[NorCalX]

I just used my test kit for the first time and am also getting different values from the expected standard

I have the speed stir and the nice bright light to help with color.

Is there an acceptable margin of error with the test results?

My CH should be 200 according to standard but multiple tests have given me 250

 

[ajw22]

My CH should be 200 according to standard but multiple tests have given me 250

Sounds like you have a drop size issue with your testing methods.

Wipe the tip between each drop to eliminate static electricity and hold the bottle vertical and let the drop fully form and fall from the tip without squeezing and forcing it off the tip.