Hello, I have a question about CYA testing. I have both a TF-Pro (salt) and a Taylor-2006C kit (science dork here). I know the reagents all come from Taylor, and fortunately, all of my results match up when comparing (even the pH, which is a different reagent for each kit). But, the cylinders for CYA make a big difference. The small clear tube from the TF kit reads lower than the dark large block from Taylor. This results in the dot disappearing at a higher number in the Taylor block vs. the TF cylinder. I have checked this in every which way - made new solutions, poured solution from one cyclinder to the other, read indoors, read outdoors. The darkened Taylor block always tests higher. I am currently SLAMing the pool after being on vacation for 2 weeks and was assuming my CYA was 30. But in the Taylor block, it always tests at 40. When I read the results outdoors, the dot disappeared even sooner. This make a difference of 4 ppm for the SLAM chlorine level. If my CYA really is 30, will 16 ppm FC hurt anything? I have been running it at 12 for the past 4 days. Chlorine loss has slowed dramatically and CC has reduced to 0.5 ppm every time I test, but I am still not there. Pool wasn't so bad that I couldn't see my main drains when I returned. It was just slightly green and cloudy. I have an autocover which is why I tend to keep CYA a little lower. I really just want to make sure I am shooting for the right target as far as FC goes for the SLAM.
CYA Testing - Kit Comparisons and Consequences for SLAM
- Thread starter Malgal
- Start date
- Jun 24, 2021
- 9,075
- Pool Size
- 30000
- Surface
- Vinyl
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-60
If you are making progress, then I would say your CYA is 30. You always want to test outdoor, sun to your back, if you test indoors, as you found, you will think your CYA is higher. Do a quick glance.
If you want to know what it should look like when dot disappears, you can order a standard solution...
tftestkits.net
If you want to know what it should look like when dot disappears, you can order a standard solution...
R-7065 CYA Standard 50ppm (2oz)
Thanks. The issue isn't that I can't read it, it is that the two different cylinders give me a different reading. The dark one that comes with the Taylor test kit gives a higher reading. The dot disappears by 40. The clear one from TF doesn't disappear at 40. The outdoor/indoor thing only seemed to matter for the Taylor block with the dark sides, but I actually have the opposite problem - indoors reads lower because the dot is easier to see. I never second-guessed my CYA reading until I got the Taylor test kit LOL. I prefer the TF kit, and I will forever advocate that one for complete newbies, but I like to be able to verify my results, and I wanted the booklet that comes with the Taylor kit. #foreverascientist
- May 23, 2015
- 24,694
- Pool Size
- 16000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
As @PoolStored alluded too - you have to do you!
What you need to do is get the CYA standard solution and then test with whichever tube/comparator floats your boat. Then you need to adjust your test conditions (lighting, time of day, squinty eyeball, look away/look at the black dot, etc, etc) until you find the conditions that get you to an exact 50ppm reading on the standard. Then you use those conditions every time.
It goes without saying that the CYA turbidity test is probably one of the most subjective and error prone tests in either kit. But short of purchasing a very expensive turbidity nephlometer and spending lots of time keeping it properly calibrated, there’s not much else you can do. I get it, you’re a “science dork” and you want exact perfection … ain’t gonna happen with swimming pool water. You’ll just have to learn to embrace the uncertainty … always a good life skill to practice
What you need to do is get the CYA standard solution and then test with whichever tube/comparator floats your boat. Then you need to adjust your test conditions (lighting, time of day, squinty eyeball, look away/look at the black dot, etc, etc) until you find the conditions that get you to an exact 50ppm reading on the standard. Then you use those conditions every time.
It goes without saying that the CYA turbidity test is probably one of the most subjective and error prone tests in either kit. But short of purchasing a very expensive turbidity nephlometer and spending lots of time keeping it properly calibrated, there’s not much else you can do. I get it, you’re a “science dork” and you want exact perfection … ain’t gonna happen with swimming pool water. You’ll just have to learn to embrace the uncertainty … always a good life skill to practice
With the vagueness and all, they can be 10 apart and still both right. Especially if the actual value is in between the two.
Pick one and stick with it. Once your CYA level holds FC properly, you're looking for change. Specifically for those of us in the northeast, dilution from rain overflow.
No matter what you called your baseline, if you lose 20, you need to add 20.
Being 10 off won't appreciably affect your sanitizing ability. Many of us 'run hot' and it's covered either way.
Pick one and stick with it. Once your CYA level holds FC properly, you're looking for change. Specifically for those of us in the northeast, dilution from rain overflow.
No matter what you called your baseline, if you lose 20, you need to add 20.
Being 10 off won't appreciably affect your sanitizing ability. Many of us 'run hot' and it's covered either way.
Apologies for the tardy "thank you!" Life and all. I attempted to stop stressing, pool cleared up. All is well! CYA is forever going to give me a headache. I didn't even finish my SLAM. We got days of thunderstorms so I closed it all up and hoped for the best. Numbers are acceptable, and the pool is clear. I am trying to embrace the uncertainty! Thanks for the life advice 