Another Taylor 2006 pH question

[cj133]

So,
I know this is an issue but I don't know how much of an issue and when.

From what I recall, if your fc is above 10ppm the pH measurement will not work correctly. Is this true?
My fc measured 8.2ppm last night and I checked my pH 4 times and all 4 times it came up high.
I'd call it purpl-ish red, or above 8. More purplish than 8 for sure.

The last time I checked it, it was running between 7.6 and 7.8 but not quite 7.8, so I added a few swig's of acid and let it sit for about a week. Since then we've had about an inch of rain. I knew I wanted to bring it down a hair, but not much. All summer it ran a solid 7.6 but I recently added some water so I expected it to go up a tad which is what the slight climb was from but it seemed to stop just under 7.8.

Now it's either reading off the scale some how, or, the fc of 8.2 is skewing it. I also tried adding a drop of R-0007 Thiosulfate and that seemed to have no effect. I can't imagine it's above 8 after I added acid and it wasn't even 7.8 last time.

Is 8.2 fc high enough to cause a slight issue, or is my test legitimate?

 

[Mdragger88]

It is not accurate @ fc levels above 10ppm.
You can dilute the sample to get a better reading, here’s the how tosection 2.2

PH - Further Reading

www.troublefreepool.com

 

[cj133]

It is not accurate @ fc levels above 10ppm.
You can dilute the sample to get a better reading, here’s the how tosection 2.2

PH - Further Reading

www.troublefreepool.com

So, at 8.2fc is it 100% accurate, or can it be skewed some?

 

[Newdude]

So, at 8.2fc is it 100% accurate, or can it be skewed some?

It should be fine to test at 8.2 FC.

Side note: switch to 10 ml FC tests and each drop is 1/2 FC. You'll save 2.5X the supplies. There is zero reason to test less than .5 FC. I care about the numbers before the decimal point and I don't care in the least about the numbers after the decimal. An 8.2 or 8.5 are awesome and a 2.2 or 2.5 suck. (for most CYA levels at least)

 

[cj133]

It should be fine to test at 8.2 FC.

Side note: switch to 10 ml FC tests and each drop is 1/2 FC. You'll save 2.5X the supplies. There is zero reason to test less than .5 FC. I care about the numbers before the decimal point and I don't care in the least about the numbers after the decimal. An 8.2 or 8.5 are awesome and a 2.2 or 2.5 suck. (for most CYA levels at least)

I've considered using .5 for everything but still haven't made my self do it.
Last night I did my first test using .2 and then my second test using .5.

 

[Newdude]

Last night I did my first test using .2 and then my second test using .5.

Neither test changed the price of beer, or the PH reading. Save your stash.

Back to the question, alot can happen in a week. What's your TA ?

 

[cj133]

Neither test changed the price of beer, or the PH reading. Save your stash.

Back to the question, alot can happen in a week. What's your TA ?

No idea right now.
Was a busy two weeks with a lot of getting home after dark, and or rain etc. I've found testing pH in the dark is useless, and even testing fc is less than fun.

If the pH is actually high I'm guessing my TA went up. It's still fairly nasty out but I'm going to have to make time to get some accurate tests.

 

[Mdragger88]

Pro tip*
take your sample into the kitchen to test or use your phone as a backlight. I often open my browser for a blank white screen when testing the hot tub after dark.