What if the cya test used lines or a letter instead of that (insert adjective here) dot?

[Poolnerdgrandma]

So the dot gets fuzzier until it (subjectively) "disappears." What if they used a different shape or symbol? Could that make consistent readings easier?

 

[Texas Splash]

What if they used a different shape or symbol? Could that make consistent readings easier?

I suspect those that first engineered this method determined through various experiments with shapes, colors, lighting, etc that the dot method would be a consistent and somewhat reliable method. It certainly can be challenging at times, but even with an allowed variance of about 10-15 ppm it's quite reliable. When I'm doing the CYA test, I repeat it several times with the same sample solution and remind myself to just glance and not stare so hard & long that I'm trying to force the dot to appears. A quick look, I either see it or I don't. But like the color shading of the pH test, that's basically what we have for now.

 

[Orion7319]

Some of us have been picking up this standard solution. If your in doubt this should help. You just use it instead of pool water and run a test. It’s calibrated at 50ppm. That way you know what the test is supposed to look like. To me it seems like a good idea and should be useful for those who aren’t comfortable doing the CYA test.

R-7065 CYA Standard 50ppm (2oz)

tftestkits.net

 

[mgtfp]

The Australian Clear Choice Labs CYA viewing tube uses a symbol instead of a dot:

CYA Viewing Tube – Clear Choice Labs

Working for me. Don't know whether that's better or worse than a dot, don't have a Taylor tube to compare.

 

[JamesW]

A blinking dot would probably work well.

 

[Newdude]

*engineers during beta testing*
This test will be very difficult to perform consistently between users.

The CEO who couldn't care less:

 

[Pauls234]

The standard solution was super helpful for me because it showed me what Taylor means by dot "just disappearing".

To me it looked like 50ppm (intended result) indoors in my kitchen, but 40 if I follow the standard TFP direction of outside middle of day, back to the sun.

So now I trust what I see testing in my kitchen then go outside and if it appears ~10 lower it further confirms.

 

[JoyfulNoise]

You actually don't want to use something complicated or familiar because your brain will "strain" to make it out. In other words, if you stare at it intensely enough, you can make out the dot way past when you should call it "occluded" and that's because our brains and retinas are incredible at pattern recognition. We are designed by nature to spot "something" moving in the bush without actually knowing what that "something" is. Then other parts of our brain tell us to pounce on it or run for the hills.

At the end of the day, you're being too particular about this test. Just use the process outlined in the testing article about sequentially filling the tube up to each known line and then quickly glancing to look for the dot. Once it disappears, call it done. You don't need to be anymore specific than that. And using the calibration solution can help you to find the best lighting and positioning you need to do to be satisfied the test in complete.

I get it that everyone wants a super accurate test for CYA but it's not really possible unless you invest hundreds of dollars in a photometer and you run zero'ing and calibration standards with every test ... that is not, by definition, "trouble free" ...

 

[Katygreys]

Reminds me of the Mitch Hedberg joke:

I was watching TV and the commercial said, “You can have this product for four easy payments of $19.99.” I would like to have a product that’s available for three easy payments and one cooooooooomplicated payment. You don’t know which one it is, but one of these payments is going to be a b$%!#*!!!