I did my first CYA test tonight. I "think" it was at 50 but I don't feel 100% sure. Is the black dot supposed to be completely gone, or does seeing it faintly constitute gone?
CYA test, dot completely gone?
- Thread starter mickey4paws
- Start date
here is a nice discussion on CYA measurement technique...
http://www.poolforum.com/pf2/showthread ... light=test
http://www.poolforum.com/pf2/showthread ... light=test
Check this out from Taylor Technologies:
http://www.taylortechnologies.com/ChemistryTopicsCM.ASP?ContentID=36
http://www.taylortechnologies.com/ChemistryTopicsCM.ASP?ContentID=36
Thanks so much for the replies, and the very helpful links. One thing I did wrong was I thought you were supposed to shake it and wait 30 seconds, then do test. I see that I am supposed to shake for 30 seconds, then do test.
ideliver said:
I tried this today and finally got a decent reading based on how much CYA Dichlor put into my spa. In the past the Taylor kit would read higher. I also have 4 way test strips that include CYA and it would always have a shade lower than 30 PPM.
Not sure if including these little techiques into the pool school for testing methods for the major factors - but it would save a lot of mis-calculations due to measurment error which leads to over/under dosing of chemicals.
ideliver - Thanks.
Barry
I would somewhat qualify what was said in the link about how to do the CYA test. You want to mix for 30 seconds (longer is OK, but not necessary) -- no need to shake as you don't want to create lots of bubbles, you just want to mix back-and-forth, back-and-forth, turning it one way, then the other, then back again. The temperature of the water should be around room temperature (normal pool temp is usually OK -- if the water it too cold, then the test may not fully develop in 30 seconds).
As for viewing the tube, I talked to Taylor about this a while ago and the measurement is closest to being correct when you hold the tube in front of you looking straight down (around waste level) with your back to the sun so that the tube is in bright indirect light (if you have to do the test indoors, create bright indirect light). If you view the tube with you facing the sun or the tube otherwise in direct sunlight, then you'll get a reading that is around 10 ppm lower and probably not as accurate, but keep in mind that the test isn't perfect anyway and at least +/- 10 ppm. Nevertheless, performing the test consistently in technique gets you pretty consistent results.
Richard
As for viewing the tube, I talked to Taylor about this a while ago and the measurement is closest to being correct when you hold the tube in front of you looking straight down (around waste level) with your back to the sun so that the tube is in bright indirect light (if you have to do the test indoors, create bright indirect light). If you view the tube with you facing the sun or the tube otherwise in direct sunlight, then you'll get a reading that is around 10 ppm lower and probably not as accurate, but keep in mind that the test isn't perfect anyway and at least +/- 10 ppm. Nevertheless, performing the test consistently in technique gets you pretty consistent results.
Richard
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