FC from 9 to 1.5 in 24 hours?

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RichTJ99

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Sep 16, 2016
255
Katonah NY
Hi,

Yesterday at 4:30 I tested my water:

FC - 9 ppm (just added LC only)
PH - 7.0 ppm
CC -12 ppm
CH - 175ppm
TA - 110
CYA - 50

I had swapped a bunch of water as my CYA was too high.

I have a 600 gallon hot tub that runs 24/7 @ 102F.

I was in the hot tub 3 times (with my sons) over the 24 hour period.

According to pool math adding 2.5 ounces of 12.5% LC should raise me to 5ppm.

I just added that & my FC (after 30 minutes) was about 2.5ppm. I am using the TFP testkit (the big one) for the FC testing.

Any ideas what I am doing wrong?

Thanks,
Rich
 
Hi,

I am going to go run the test again but I think I wrote that down wrong. I am guessing it must have been 12 drops (or 6ppm)?

I am going to do another FC & CC test right now:

10 minutes later:

OK so right now its

FC: 2.5
CC: 1

I might put another 2.5 ounces in tonight & see where i end up. I think I want to be at 5 for the FC.

Though that would make the current TC 3.5?


EDIT: I am using the TF100 kit & these instructions: TFTestkits.net
 
RichTJ99 said:
Hi,

Yesterday at 4:30 I tested my water:

FC - 9 ppm (just added LC only)
PH - 7.0 ppm
CC -12 ppm
CH - 175ppm
TA - 110
CYA - 50

I had swapped a bunch of water as my CYA was too high.

I have a 600 gallon hot tub that runs 24/7 @ 102F.

I was in the hot tub 3 times (with my sons) over the 24 hour period.

According to pool math adding 2.5 ounces of 12.5% LC should raise me to 5ppm.

I just added that & my FC (after 30 minutes) was about 2.5ppm. I am using the TFP testkit (the big one) for the FC testing.

Any ideas what I am doing wrong?

Thanks,
Rich
Click to expand...
Are you perhaps confusing CC with TC? TC is the sum of FC (good stuff) + CC (bad stuff), or FC + CC = TC
 
Hi,


So as of last night my FC was 8 & CC was 1 so I guess my TC would be 9?

Again based on pool math, with my FC at 1 & goal of 7 with a 600 gallon tank, using 12.5% bleach I should have needed 3.7 oz but used 7.5 (and ended up at 8 FC).

Based on 7.5oz of 12.5% pool math says my FC should be at 13.

I am a bit confused or something else may be off?



I am using this as my guide:

Chlorine Drop test - If you need to......1) measure Chlorine levels accurately or 2) higher than 5ppm or 3) test for Combined Chloramines…perform the Chlorine Drop Test. (FAS/DPD)
1. Rinse and fill the “Chlorine only” graduated cylinder to the 10mL mark
2. Add ONE heaping scoop of the R-870 powder and swirl to mix. (It may not all dissolve….don’t worry) The solution will turn pink. (unless you have no chlorine)
3. Next, carefully add R-871 solution one drop at a time. Count each drop and swirl until the solution turns back to clear. Multiply the number of drops you added times .5 (14 drops X .5 = 7ppm)
4. Record your results as FC (free chlorine)
5. To test for Combined Chloramines, add 5 drops of R-0003 to the solution and swirl. If it remains clear, you have no CC’s. If it returns back to pink, add R-0871 as before, counting and swirling between each drop. Once the solution returns clear, multiply the added drops times .5 again…..this will be your CC reading. Record it. The total of FC and CC should be recorded as TC (total chlorine)


What I am doing:
10ML + scoop of powder + Mix
Add 871 while mixing counting drops
Divide drops by 2 to get FC
Then add 003 (5 drops) (gets pink)
Add 871 while mixing / counting drops
Divide drops by 2 to get CC
 
RichTJ99 said:
Hi,


So as of last night my FC was 8 & CC was 1 so I guess my TC would be 9?

Again based on pool math, with my FC at 1 & goal of 7 with a 600 gallon tank, using 12.5% bleach I should have needed 3.7 oz but used 7.5 (and ended up at 8 FC).

Based on 7.5oz of 12.5% pool math says my FC should be at 13.

I am a bit confused or something else may be off?



I am using this as my guide:

Chlorine Drop test - If you need to......1) measure Chlorine levels accurately or 2) higher than 5ppm or 3) test for Combined Chloramines…perform the Chlorine Drop Test. (FAS/DPD)
1. Rinse and fill the “Chlorine only” graduated cylinder to the 10mL mark
2. Add ONE heaping scoop of the R-870 powder and swirl to mix. (It may not all dissolve….don’t worry) The solution will turn pink. (unless you have no chlorine)
3. Next, carefully add R-871 solution one drop at a time. Count each drop and swirl until the solution turns back to clear. Multiply the number of drops you added times .5 (14 drops X .5 = 7ppm)
4. Record your results as FC (free chlorine)
5. To test for Combined Chloramines, add 5 drops of R-0003 to the solution and swirl. If it remains clear, you have no CC’s. If it returns back to pink, add R-0871 as before, counting and swirling between each drop. Once the solution returns clear, multiply the added drops times .5 again…..this will be your CC reading. Record it. The total of FC and CC should be recorded as TC (total chlorine)


What I am doing:
10ML + scoop of powder + Mix
Add 871 while mixing counting drops
Divide drops by 2 to get FC
Then add 003 (5 drops) (gets pink)
Add 871 while mixing / counting drops
Divide drops by 2 to get CC
Click to expand...
I'm guessing that the bleach is not 12.5%, or the volume of the tub is much larger.
 
how old is the bleach and where is it stored?

as a benchmark, go buy some brand new 8.25% that you know is going to be 8.25%, then perform your tests and compare the relative percentages.

also, heat degrades CL and so does body count, as well as clear skies and full sun. You need to track your testing variables and see if that has any impact too.
 
tstex said:
how old is the bleach and where is it stored?

as a benchmark, go buy some brand new 8.25% that you know is going to be 8.25%, then perform your tests and compare the relative percentages.

also, heat degrades CL and so does body count, as well as clear skies and full sun. You need to track your testing variables and see if that has any impact too.
Click to expand...

I got the bleach from my pool supply store at the end of the season. The room its in is a bit hot (hot tub is indoors). It could be just old stock they were pushing on sale?

I will stop by target today & get some new bleach for testing purposes.
 

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pabeader said:
There may be a date code on the stuff you got from the pool $tore. Look for a code like "16349 8:34" That would be the 349th day of 2016.
Click to expand...

Its 16221. I didn't make it to the store today but we'll plan to get some bleach tomorrow.

I did go test the water and it went from 8 part per million last night at 10:30 p.m. till one part per million at 7:30 p.m. tonight period

I added 5 ounces of 12% bleach and a product of 4 parts per million

I'm going to likely add another two and a half ounces and see where that gets me. But if the bleach is compromised I'm probably wasting my time.

Thanks

Rich


Edit I must be a little impatient. The 5 oz brought it to 7 ppm.
 
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