CYA tests

[Bry17]

I have been using my Taylor CYA test and reading about 50 ppm. I decided to get a test at the pool store because my FC was disappearing very quickly. It dropped from 3.3 to 0.8 in a day once. The store used a Pentair tube and got 30 ppm. This was a couple weeks ago. I decided to slowly bring it up using trichlor tabs in my inline feeder (usually use bleach). I tested it today. I am still getting 50 on the Taylor test (we have had some heavy rain lately, though) and a little less than 30 on my Pentair test I just bought. I am not sure which to believe. I wish there was a way to get a reliable reading!

I had some slight algae in one of the dead area in my pool today with an FC of 2.2. If the CYA was 30, 2.2 should be fine, so this points me towards believing the 50. But the chlorine is disappearing so fast pushes me towards believing the 30.
Any ideas? Any experience comparing the results of the 2 tests?

 

[Texas Splash]

Welcome to TFP! I would always trust my own testing before the pool store. The only issue may be the age of your reagents. Normally the R-0013 CYA reagent is quite reliable for a while, but that's something to watch. As for the chlorine loss, I would start with an Overnight Chlorine Loss Test first to confirm algae. It sounds as though you might have some, so if so, then perform the SLAM Process right away and maintain the appropriate FC SLAM level until you pass all 3 SLAM criteria. Hope that helps.

Pool Care Basics Archives

Your one-stop shop for all things TFP to include: ABCs of Water Chemistry, Recommended Chemicals/Levels, Test Kits, Troubleshooting, and much more!

www.troublefreepool.com

 

[Bry17]

Welcome to TFP! I would always trust my own testing before the pool store. The only issue may be the age of your reagents. Normally the R-0013 CYA reagent is quite reliable for a while, but that's something to watch. As for the chlorine loss, I would start with an Overnight Chlorine Loss Test first to confirm algae. It sounds as though you might have some, so if so, then perform the SLAM Process right away and maintain the appropriate FC SLAM level until you pass all 3 SLAM criteria. Hope that helps.

Pool Care Basics Archives

Your one-stop shop for all things TFP to include: ABCs of Water Chemistry, Recommended Chemicals/Levels, Test Kits, Troubleshooting, and much more!

www.troublefreepool.com

Thank you. I will give that a try when it stops storming.

 

[Bry17]

I just performed the OCLT. My FC dropped from 6.8 to 5.8, so it’s right on the threshold. Appears to not be a big problem. I have performed the CYA test myself using both tools mentioned above, getting 30 with Pentair and 50 with Taylor. Wish there was a trustworthy store nearby!

 

[Texas Splash]

Wish there was a trustworthy store nearby!

Stores will most often give you a more unpredictable result, especially for the CYA. You're better off trusting your own results. You got this!

 

[PoolGate]

You might also consider getting the 50ppm Taylor reference sample. Use it to fill your CYA test tube to 50, and see what you see for the dot. This will guide you in your actual testing as to what to look for.

Hint: the dot doesn't actually disappear when you have an accurate reading!

R-7065 CYA Standard 50ppm (2oz)

tftestkits.net

 

[Bry17]

You might also consider getting the 50ppm Taylor reference sample. Use it to fill your CYA test tube to 50, and see what you see for the dot. This will guide you in your actual testing as to what to look for.

Hint: the dot doesn't actually disappear when you have an accurate reading!

https://tftestkits.net/R-7065-CYA-Standard-50-ppm-2-ou nces-p97.html

Thanks! Do you mix this with the reagent, or is it good to go as-is?

 

[PoolGate]

Thanks! Do you mix this with the reagent, or is it good to go as-is?

Yes - mix as usual with 50/50 reagent but fill the tube to 50 and that is the final result.

 

[Rancho Cost-a-Lotta]

Thanks! Do you mix this with the reagent, or is it good to go as-is?

I haven't used the standard, but I believe you still need to use the R-0013 reagent.

From TFP Wiki:

CYA Standard Solution​

You can buy CYA 50 Standard Solution to practice on and see what the dot should look like at the CYA 50 end point.

Directions for R-7065 (CYA 50 Standard Solution)​

1. Fill the red-capped CYA mixing bottle to the bottom of the label with R-7065 (it is the “pool water”). Now, fill the bottle to the top of the label with R-0013 (in 8 oz. bottle).* Mix then wait at least 30 seconds. Mix once more.

2. Next, get the clear tube marked CYA View Tube and holding it at waist level (so you can look down into tube) slowly fill the view tube with the solution you have mixed. Keep filling until you no longer see the black dot in the bottom of the tube. *You should have a reading of 50 ppm, give or take 5 ppm.

 

[PoolGate]

I haven't used the standard, but I believe you still need to use the R-0013 reagent.

From TFP Wiki:

CYA Standard Solution​

You can buy CYA 50 Standard Solution to practice on and see what the dot should look like at the CYA 50 end point.

Directions for R-7065 (CYA 50 Standard Solution)​

1. Fill the red-capped CYA mixing bottle to the bottom of the label with R-7065 (it is the “pool water”). Now, fill the bottle to the top of the label with R-0013 (in 8 oz. bottle).* Mix then wait at least 30 seconds. Mix once more.

2. Next, get the clear tube marked CYA View Tube and holding it at waist level (so you can look down into tube) slowly fill the view tube with the solution you have mixed. Keep filling until you no longer see the black dot in the bottom of the tube. *You should have a reading of 50 ppm, give or take 5 ppm.

Ah - ok yes it has been awhile sorry I posted the wrong answer. Yes, still need to mix 50/50 with reagent!