Just did my first test and feel kinda LOST...

IronMike

Member
Apr 22, 2020
15
Brentwood, CA
Yes. I bought these liquid chlorine two weeks ago. The dates on the box is Julian dates 20076. That’s roughly March 16, 2020, and that should be manufacture date not the expiration date, correct? If that’s the case, what else did go wrong that my FC remains zero? Thanks again!

Mike
 

IronMike

Member
Apr 22, 2020
15
Brentwood, CA
Now my FC test result is 4.4ppm. This is after adding a total of 2 gallons of liquid chlorine and 70-80% water change.

1. Just to confirm, the Julian date on the liquid chlorine box is in fact the manufacture date not the expiration date, correct?

2. Since my CYA is around 55-60, my next step is to raise my FC to 7-9 range according to the FC/CYA chart, correct?

Thanks again!!

Mike
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
21,204
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
CYA of 60 target FC is 7-9. Add another gallon of LC and test again.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
21,204
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
The Taylor test kit can measure FC and CC to the tenth of a ppm? I have the TF100 kit and it measure by the 1/2 ppm (1/2 ppm per drop).
Use a 25 ml sample and the TF100 will also be .2 ppm a drop. You do use a lot more reagent for unneeded precision.
 

IronMike

Member
Apr 22, 2020
15
Brentwood, CA
CYA of 60 target FC is 7-9. Add another gallon of LC and test again.
My family member helped me to add 0.75 gallon of LC with the pump on this afternoon. I just tested my FC, and it’s 5.2.

1. Is it because my PH is slightly high 7.8-8, so it’s affecting how LC is reacting in my pool? Should I add muriatic acid to slightly bring down my PH before adding my more LC?

2. With my CYA being 60, I understand that my ideal FC should be between 7-9 ppm. However, according to other studies online, the suggested FC should be between 2-4 ppm. “Any higher will make you run the risk of red eyes and swimmers itch.” How can I properly explain this to my family?

3. What should be my next action?

Thanks!

Mike
 

IceShadow

Gold Supporter
TFP Guide
Jun 8, 2019
2,177
Milwaukee, WI
When testing FC, use a 10ml sample and a heaping tiny scoop of powder. Each drop then is 0.5ppm of FC. Will save you reagents.

1) You can bring it down a bit. Aim for 7.6, and if it ever goes to 8, lower to 7.6 again. It doesn’t affect the FC very much at all but it’s good practice.

2) Old recommendations that don’t take the CYA/FC relationship into account are everywhere. You’ll see plenty of rebuttal on the forums, and there’s threads with scientific information to back it up. The 2-4ppm recommendations don’t even have a CYA recommendation, and 7-9 ppm with CYA of 60 is less harsh than 1ppm FC with no CYA at all. Red eyes are typically from CCs, and most people get those because their FCs are too low compared to their CYA.

3. If your pool is crystal clear, keep testing daily and bring it back up to a target of 9ppm. After a week or two you’ll get used to how much you’re adding and can test three or even two times a week instead to keep an eye on things.
 
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ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
21,204
Northern NJ
Pool Size
35000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
How many gallons in your pool?

Post pics of the labels on the liquid chlorine you are using.

Your pH does not effect the way chlorine is reacting in your pool.

Why did you add .75 gallon and not a full gallon?

You had your FC up to 9ppm on 4/25 with 2 gallons. What is different between then and now?
 
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duraleigh

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Apr 1, 2007
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Sebring, Florida
The Taylor test kit can measure FC and CC to the tenth of a ppm? I have the TF100 kit and it measure by the 1/2 ppm (1/2 ppm per drop).
The FC tests are identical. It's the sample size of pool water that determines the resolution.

A resolution of .5 ppm is all that's need for practicing TFP methods so we suggest a 10 ml pool sample be used for either kit.
 
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IronMike

Member
Apr 22, 2020
15
Brentwood, CA
How many gallons in your pool?

Post pics of the labels on the liquid chlorine you are using.

Your pH does not effect the way chlorine is reacting in your pool.

Why did you add .75 gallon and not a full gallon?

You had your FC up to 9ppm on 4/25 with 2 gallons. What is different between then and now?
My pool is 16,000 gallons, and below is a picture of the LC I was using. On 4/25, I was using the HDX LC that I bought from Home Depot last year, and I was able to raise my FC to 9ppm back then. Since I went out of HDX LC, I bought the KEMTEK LC from Lowe's a couple weeks ago. I reported my FC was 5.2ppm after I added 0.75 gal of LC, so I went ahead and did a full water test this morning, and I didn't believe my FC result below:

FC: 0.4 ppm
PH: 8
TA: 160
CH 450
CYA: 60

Without doing anything to the water in between my FC tests from last night until this morning, my FC drops from 5.2 ppm to 0.4 ppm. I'm sure most of you would think that I'm crazy, so I went to the pool, took a different water sample and tested the FC again, and I got the same result 0.4 ppm. I noticed the pink color was really light after I added two scoops of powder to my 25ml sample (I'm still doing the 25ml for now until I can get a more stable result), and it only took 2 drops of R-0871 to turn pink to colorless in both tests. I'm new, but I follow the same procedure every time I do these tests.

I really don't know what I'm doing wrong. I know I could have added LC during night time for better result, but I don't think it will make that much of difference. The labels on both HDX and KEMTEX are almost identical. I drilled two (pencil thick) holes on the LC bottle cap and let the LC pour in front of my return pump. I sometime would also walk around and pour it LC around the pool hoping it will circulate better. Anything else I'm missing?

After the water test (FC: 0.4ppm) this morning, I went ahead and added 1.25 gal of LC to the pool with the pump running of course. It's been about 30 minutes now, so I will go ahead and do another FC test soon and report back. However, any specific reason why my FC result can vary that much? Thanks again everyone!!

Mike

image0-2.jpeg
 

IronMike

Member
Apr 22, 2020
15
Brentwood, CA
I did a water test for FC and PH again today.

FC: 5ppm
PH: 8

1. I haven’t added any LC since I added 1.25 gal LC yesterday and got 10.6 ppm FC, but it drops to 5ppm in a day. Is this normal? If not, how many ppm does it normally drop in a day?

2. My PH remains high at 8, and I plan to drop my PH to the ideal range 7.6-7.8 using muriatic acid. Just want to confirm if this is a right time to drop. Should I wait until I have a stable FC first or it doesn’t really matter?

Thanks!

Mike
 

mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,892
Laughlin, NV
5ppm FC loss in a day is on the high side, but just keep your FC in the target range for your CYA and see how it averages out. You do need to add liquid chlorine every day.

Adding a bit of acid to lower the pH to 7.6 is fine.