FC and CYA levels testing (tfp-100)

[tarungogia]

I got the TFP-100 kit today. Was testing FC and CYA levels. Need some confirmation.
I am not sure if i got the correct readings.

For CYA - I followed the instructions. i added pool water to cya mixing bottle and mixed R-0013 and then started filling the tube "CYA VIEW TUBE" - i was able to fill the whole tube all the way till mark - 20 but black dot was still visible. DOES THAT MEAN my CYA levels are very low ?

FC - i had added a jug (2G) of liquid chlorine about a week back to the pool. today when i got the kit, i wanted to test FC levels. I followed the instructions and am getting more than 7ppm as the result. Is it possible to have these high levels even after a week.

 

[jseyfert3]

For CYA - I followed the instructions. i added pool water to cya mixing bottle and mixed R-0013 and then started filling the tube "CYA VIEW TUBE" - i was able to fill the whole tube all the way till mark - 20 but black dot was still visible. DOES THAT MEAN my CYA levels are very low ?

Yes, it means it's below 20 ppm. Was the water cloudy at all in the test tube while you were looking down it at the dot?

I see in your prior thread you said the store tested a stabilizer (CYA) level of 30. They likely used a Taylor test kit, which only goes to 30 on the low end, unlike your TF100 kit that goes to 20. Either way, they are in line with each other and indicated a low CYA level.

FC - i had added a jug (2G) of liquid chlorine about a week back to the pool. today when i got the kit, i wanted to test FC levels. I followed the instructions and am getting more than 7ppm as the result. Is it possible to have these high levels even after a week.

That seems unlikely to me, given your low CYA level, as even 12.5% chlorine only adds 13 ppm FC to a 19,700 gallon pool, and you said you were at 1 ppm a week ago. What percentage of chlorine did you add? Did you happen to get the Speedstir when you bought your test kit? What sample size of water did you use (10 or 25 mL), and how many drops of R-0871 did you add when doing the test? What is your current water temp?

 

[tarungogia]

Hi @jseyfert3 - thanks for your reply.

regRding chlorine levels, I followed the instructions for the test kit. 10 ml of pool water.
Regarding R-0871 , I added about 15 drops shaking the container after each drop till the solution became completely clear. I dont have the speedstir.
I Don’t have a temp gauge for the pool ( I will get one soon). If I had to guess , it must be around 80F ( am here in south Florida) and I took temp at around 5 pm in evening and it was hot during the day.
Regarding percentage of chlorine , I got the chlorine jug from pool store ( pinch / penny). It says on container -10.5% sodium hypochlorite.
Am I doing the test wrong ?

 

[jseyfert3]

Am I doing the test wrong ?

I'm not certain.

regRding chlorine levels, I followed the instructions for the test kit. 10 ml of pool water.
Regarding R-0871 , I added about 15 drops shaking the container after each drop till the solution became completely clear. I dont have the speedstir.

Can you clarify what you mean by "shaking"? Refer to this guide, noting two things that stand out to me. The motion you want is "swirling", though that may be what you meant by shaking. The second is this test is somewhat time critical, and should be performed at a rate of at least one drop per second with continuous swirling through the entire process, only slowing down near the end so you don't overshoot the clear point transition.

Video demonstration by TFTestkits:

Note this is somewhat tricky and requires a bit of coordination. It's made much easier by the Speedstir, which eliminates the need for manual swirling.

If this test is performed over too long a period of time, it can report a higher than actual FC level, as the sample will slowly turn pink over time. I'm not certain this is what is going on at your pool though. Do you have a saltwater chlorine generator by chance? Did you add anything to the pool since a week ago when you reported a FC level of 1.0 and added two gallons of 10.5% chlorine?

 

[tarungogia]

tHANKS @jseyfert3 for videos. I guess i was not swirling enough. I tried doing the test again manually swirling while dropping the chemical and got the result as 5ppm for FC which is more in line. I will order speedstir for next test.

For CYA - i will get Clorox Pool&Spa Chlorine Stabilizer to increase cya levels (will out them in a sock in the skimmer). Will post the results back.

 

[ajw22]

Yes, your CYA is low and you should add stabilizer by the sock method to raise it to around 30 ppm.

Is your pool inside a cage with a roof? In the winter and with a roof your pool will not consume much FC a day. Your testing sounds fine. Test daily and learn what your average daily FC loss is.

 

[BowserB]

FWIW. I hand swirled for a year before I decided to try the speedstir. OMG every time I use it I kick myself for waiting so long to get it. It's like the difference in making a vegetable protein health shake with a blender compared to a spoon. The speed stir even has a light in the base to help see the solution color. Get it today.

 

[tarungogia]

Yes, your CYA is low and you should add stabilizer by the sock method to raise it to around 30 ppm.

Is your pool inside a cage with a roof? In the winter and with a roof your pool will not consume much FC a day. Your testing sounds fine. Test daily and learn what your average daily FC loss is.

Yes pool is screened ( no roof though). I will test these fc levels and try to see the loss pattern.