PH test, do I need my eyes adjusted?

[rajung]

Something I have wondered about for some time.
When doing the PH test my level always is between 7.6 and 7.8.
But I noticed if I turn the "test box" ? horizontal with cap on, the colors will be slightly off?
If its 7.6 it may show 7.8 and vise a versa. yes, I must be bored .

 

[Texas Splash]

Those colors can play tricks on my eyes as well. I have the most difficulty between 7.4-7.4. But when the occasion comes along I have to lower my pH to the low 7s, making it orange helps give my eyes a good reference and something easy to compare to. I also found that experimenting with different backgrounds has helped.

 

[rajung]

Yup.
I first noticed when I used MA to lower the TA and tried to get the PH down to 7.2 and no lower.
It just seemed easier and more pronounced when turned on its side.

 

[kellyfair]

Huh. Never tried that!

 

[Derb22]

I have to ask my kids. It seems 7.8 - 8.0 is hard for me to tell. It’s may be an age thing. They take one glance and tell me right off.

 

[rajung]

I have to ask my kids. It seems 7.8 - 8.0 is hard for me to tell. It’s may be an age thing. They take one glance and tell me right off.

that's funny, same for me, 7.6 or 7.8 hard to tell until I turn vial sideways then it is easier to see difference.
Good thing tests aren't done by sound

 

[KerryR]

That's a cool trick. I'll try it.

Here's what I do: Bring the test cell right up to my eye, letting my vision "blur". I hold a white card several inches behind this with the other hand, tilting it to light it well. I look through the test cell at the white card (everything's blurry), then rapidly slide over to the color comparison slats. A few "flashes" back and forth and I can pretty easily figure out pretty precisely where the test water falls compared to the color slats. Bringing the cell close to the eye removes external stimulus that can alter color perception. At this close range, the color almost completely fills the field of view, and minor differences in color are pretty easy to see when you "flash" back and forth.

This works for the chlorine (OTO) test as well, assuming your CL target is low enough to work.

Be careful; ensure you don't spill or splash reagent and test water into your eye. I've never come even remotely close to doing so, but it's a valid concern.

 

[SMH2]

I just picked up the PH meter at TFTestkits. For daily testing it is my go to as I don't feel I can accurately tell what the heck color the drop test is.

 

[ctrav]

The tricks just keep on coming

 

[KerryR]

Despite what I think is a cool trick (block close to eye), I ordered a Ph meter from TFT, too...