CYA Testing - Back to the sun, but...

[Roguewave]

Good afternoon,

Taylor K-2006C

With my back to the sun and the tube waist high, should the tube be shaded by my body? Or...?

 

[HermanTX]

Yes. But here is an alternative method that may help.
Rather than looking down the tube while you are squirting the sample this is my recommendation.
Make your mixture as directed. Then pour it to a set known level that is higher then your current CYA. Let’s say it is 80. Pour to the 80 mark and confirm that you can see the dot. Then pour sufficient mixture to the 70 mark. Then look again. If you see the dot, continue by pouring again to the 60 mark. Do this until you do not see the dot. Then use the mark that you last saw the dot as your CYA. This does 2 things. 1 - you only look in the tube after you pour to the next decade mark so you are not constantly looking at the dot. 2- this maintains that you only report your CYA in decade numbers. You do not want to interpret between the decade lines as it is a logarithm scale, therefore not uniform between the decade numbers.

 

[Roguewave]

Good afternoon,

Taylor K-2006C

With my back to the sun and the tube waist high, should the tube be shaded by my body? Or...?

Yes. But here is an alternative method that may help.
Rather than looking down the tube while you are squirting the sample this is my recommendation.
Make your mixture as directed. Then pour it to a set known level that is higher then your current CYA. Let’s say it is 80. Pour to the 80 mark and confirm that you can see the dot. Then pour sufficient mixture to the 70 mark. Then look again. If you see the dot, continue by pouring again to the 60 mark. Do this until you do not see the dot. Then use the mark that you last saw the dot as your CYA. This does 2 things. 1 - you only look in the tube after you pour to the next decade mark so you are not constantly looking at the dot. 2- this maintains that you only report your CYA in decade numbers. You do not want to interpret between the decade lines as it is a logarithm scale, therefore not uniform between the decade numbers.

Hey thanks, HermanTX.

Yeah. I do that. The method is listed in CYA Testing - Further Reading.

It's just that I can see the dot still if my back is to the sun, but the tube is shifted to be in the sun... per a given line. Then shifting the tube back to the shade, the dot disappears. I always ASSumed it was implied that if your back is to the sun and the tube is waist high, then the tube must be in the shade. But I've never seen that specified. And it makes a difference. Probably at least 10 ppm.

 

[HermanTX]

Hey thanks, HermanTX.

Yeah. I do that. The method is listed in CYA Testing - Further Reading.

It's just that I can see the dot still if my back is to the sun, but the tube is shifted to be in the sun... per a given line. Then shifting the tube back to the shade, the dot disappears. I always ASSumed it was implied that if your back is to the sun and the tube is waist high, then the tube must be in the shade. But I've never seen that specified. And it makes a difference. Probably at least 10 ppm.

Just be consistent. Suggest back to the sun and tube in shade.

 

[Roguewave]

Just be consistent. Suggest back to the sun and tube in shade.

Roger that. Thanks!

 

[Tres Gatos]

I don't usually trust test strips but one thing they are good for is indicating CYA no eye magic involved.

 

[poolnoobgrandma]

I don't usually trust test strips but one thing they are good for is indicating CYA no eye magic involved.

What? There are accurate test strips for CYA?

 

[Tres Gatos]

My 68 year old eyes can't see invisible black dots very well. When I drain the pool and add CYA according to pool gallons (about 30 ppm) the strip is actually pretty accurate. Of course you need to wait about a week for the CYA to dissolve to get an accurate reading.

 

[mknauss]

What? There are accurate test strips for CYA?

No. They might hit the right number randomly, but not consistently.

 

[newdude]

don't usually trust test strips but one thing they are good for is indicating CYA no eye magic involved

How does 0, 20-50, 100, 200+ really tell you anything ?