CYA Testing. Oh Brother!

[BigTallGuy]

Hi Mom and thanks Evan. I am going to finally order my own kit. I just wanted to be sure exactly how the Taylor K2006 worked. Pool Stores, Bah.

[chem geek]

The expected lighting for the Taylor CYA test is strong indirect lighting. They recommend that one stands outside with one's back to the sun so that the tube is shaded by your body and you look down straight into it. You can also buy standard solutions of 50 ppm if you want to practice, but that's overkill and only for those who are really curious or picky. I've always gotten the expected result when using the method recommended by Taylor.

[BigTallGuy]

This confirms what everyone has told me all along, even the pool store guys. The test is totally subjective. However, the condition of the testing tube (yellowed and tarnished vs. clean and clear) has to be added to the list of variables.

My expeience showed the "Pool Store" reading be higher than actual, and thus taking away the "Need" to buy more chemical.

So this kinda works in reverse. It would behoove the pool stores to use new or clean testers in good lighting in order to sell more CYA.

[famousdavis]

I have a new Taylor K-2006 kit, and tried doing my own CYA tests this weekend. I do find it hard to know how much of the black dot must be obscured to say that it has "disappeared". For instance, it pretty much disappeared at about the same level reported by one of the pool companies I've taken water samples to, but I *could* still manage to see a very faint outline of a black dot (because I knew a black dot was at the bottom). Even after filling up the tube with the remaining CYA fluid I could still kinda-sorta see a black dot at the bottom of the tube, although it was quite hard to do so. So, unlike the FAS-DPD chlorine test where "colorless" means absolutely without any color at all, I'm interpreting the black dot test to be mean that you stop when you can't easily see a black dot anymore. At the least, I'm able to replicate the pool store's numbers with a home-test kit.

[aylad]

famousdavis,
The important thing is that you do the test in consistent conditions, and if you "stop to when you can't easily.....anymore", then you do it to that same point every time. The test is very subjective, and is really a good ballpark, so if you are just consistent about it from test to test, you should be fine.

Janet

[waterbear]

The dot should not be visible. That is what disappeared means. Taylor has a video on their website that illustrates this. Click the pool/spa link on the upper right and scroll down for the CYA testing video for the K-2005 or K-2006. They are the same. As you can see in the video the black not is not visible at all.

The pool store test is not to be trusted. I used to work in one and know how people tend to test water. It is done fast to maximize the bottom line. Your own testing is going to be better if you just follow the directions and take your time. You can always pour the contents of the view tube back into the dispensing vial and add it back into the view tube to see if you get the same results.

[famousdavis]

"You can always pour the contents of the view tube back into the dispensing vial and add it back into the view tube to see if you get the same results."

Great tip!! I'll try that next time I do the CYA test. I'm off to watch that video now....