CYA test - Home/Store tests

jrbevis

Member
Sep 7, 2021
24
N Las Vegas, NV
Pool Size
8500
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-20
Hi there,
This is my first year with a pool...
I've been religiously having my water test done at my local pool store while also testing my water using my TF-PRO kit. I was doing this initially to compare the results. Now that I'm comfortable doing the home test, it's time to decide what to do about the LARGE gap between my CYA results and the store results. My readings using the black dot method are consistently at 40 the store results are consistently at 65-70.

I believe I'm following the test kit instructions as closely as possible and adding one drop at a time until I can't see the black dot in a bright room or outside.

If you were me, would you add more CYA to your pool?
Thanks
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
50,801
Laughlin, NV
Pool Size
6000
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
We all believe your testing. So use it.

If my CYA was 40, my FC loss per day would be well above 5 ppm. But at 70 ppm CYA, it is about 3.5 ppm per day.

What is your FC loss per day?
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
40,235
Texas, San Antonio/Marion, South-Central Area
Pool Size
17888
Surface
Fiberglass
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
You also don't have to add the CYA solution that slowly (ne drop at a time) as if it was an FC test. You can squirt a bit more ta a time. See the notes below in case it helps.

CYA Testing:
Proper lighting is critical for the CYA test, so you want to test for CYA outside on a bright sunny day. Use the mixing bottle to gently mix the required amounts of pool water and R-0013 reagent, let sit for 30 seconds, then gently mix again. Recommend standing outside with your back to the sun and the view tube in the shade of your body at waist level. Then, begin squirting the mixed solution into the skinny tube. Watch the black dot until it completely disappears. Once it disappears, record the CYA reading. To help the eyes and prevent staring at the dot, some people find it better to pour & view in stages. Pour some solution into the viewing tube, look away, then look back again for the dot. Repeat as necessary until you feel the dot is gone. After the first CYA test, you can pour the mixed solution from the skinny view tube back to the mixing bottle, gently shake, and do the same test a second, third, or fourth time to instill consistency in your technique, become more comfortable with the testing, and validate your own CYA reading. Finally, if you still doubt your own reading, have a friend do the test with you and compare results.
 

jrbevis

Member
Sep 7, 2021
24
N Las Vegas, NV
Pool Size
8500
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-20
We all believe your testing. So use it.

If my CYA was 40, my FC loss per day would be well above 5 ppm. But at 70 ppm CYA, it is about 3.5 ppm per day.

What is your FC loss per day?
I'm unsure what my daily loss is as I just had my SWG installed, and I'm fine-tuning it. It also doesn't help that we've had multiple cloudy days as well. Without the SWG I had to float 2-3 tabs and also use liquid chlorine maybe 10oz every other day or so.
 

jrbevis

Member
Sep 7, 2021
24
N Las Vegas, NV
Pool Size
8500
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-20
You also don't have to add the CYA solution that slowly (ne drop at a time) as if it was an FC test. You can squirt a bit more ta a time. See the notes below in case it helps.

CYA Testing:
Proper lighting is critical for the CYA test, so you want to test for CYA outside on a bright sunny day. Use the mixing bottle to gently mix the required amounts of pool water and R-0013 reagent, let sit for 30 seconds, then gently mix again. Recommend standing outside with your back to the sun and the view tube in the shade of your body at waist level. Then, begin squirting the mixed solution into the skinny tube. Watch the black dot until it completely disappears. Once it disappears, record the CYA reading. To help the eyes and prevent staring at the dot, some people find it better to pour & view in stages. Pour some solution into the viewing tube, look away, then look back again for the dot. Repeat as necessary until you feel the dot is gone. After the first CYA test, you can pour the mixed solution from the skinny view tube back to the mixing bottle, gently shake, and do the same test a second, third, or fourth time to instill consistency in your technique, become more comfortable with the testing, and validate your own CYA reading. Finally, if you still doubt your own reading, have a friend do the test with you and compare results.
Thank you.
 

sacredcow

Silver Supporter
May 8, 2018
283
Houston, TX
Pool Size
14000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Hayward Aqua Rite (T-15)
Order one of the CYA standards available at the TFTestkits and run it through the test. This gives you something to which you can mentally compare. I ultimately discovered that I was reading my CYA way high, presumably letting my brain tell me "Yeah, that's the dot. Keep going."

One of these days, I'm going to run across a used turbidimeter being retired and taken off of our asset list at work....
 

jrbevis

Member
Sep 7, 2021
24
N Las Vegas, NV
Pool Size
8500
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-20
Order one of the CYA standards available at the TFTestkits and run it through the test. This gives you something to which you can mentally compare. I ultimately discovered that I was reading my CYA way high, presumably letting my brain tell me "Yeah, that's the dot. Keep going."

One of these days, I'm going to run across a used turbidimeter being retired and taken off of our asset list at work..
 

bertschb

Bronze Supporter
Dec 11, 2021
392
Arizona
Pool Size
13600
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
This is the CYA 50ppm "Standard" we are referring to... CYA Standard
You use it in place of your pool water when testing CYA. It lets you know what a "true" 50ppm of CYA looks like when you test it.
 

VinnyinNJ

Well-known member
Jul 20, 2022
291
New Jersey
Pool Size
13500
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Hayward Turbo Cell (T-CELL-5)
I would trust your own testing as it is not a difficult test to perform. The hardest part is "do I or don't I see the dot"! You may be off a little but not by much. I always did the test 2x, once for each eye and see if it was about the same reading and it always was.
 

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jrbevis

Member
Sep 7, 2021
24
N Las Vegas, NV
Pool Size
8500
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-20
This is the CYA 50ppm "Standard" we are referring to... CYA Standard
You use it in place of your pool water when testing CYA. It lets you know what a "true" 50ppm of CYA looks like when you test it.
Roger that. I've got the standards tests coming in the mail.
Thanks
 
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