Free and Combined Chlorine not changing

LaurenB

Well-known member
Jun 4, 2014
94
Shrewsbury, PA
Alright, I'm done with the pool store and I'm a total newbie but I'm going to attempt to start the SLAM process tonight.

I work 12 hour shifts so it's going to be hard until I get to my days off...

My husband ran a FC/CC test tonight for me:

FC-10.5
CC-1.5-2

My last CYA reading yesterday was 35-40. Going with 40, and using the chart to decide SLAM, my shock level should be a 14. The pool math calculator says I need to add 100oz of 6% bleach. I'm stopping at Wal-Mart on my way home from work tonight and picking up a few gallons.

If I go a little above the 14ppm, will that be damaging to the liner? At what point DOES FC damage the liner? Last year (when following pool stores advice) I over-shocked at got an FC of 21. It didn't bleach the liner then, so I guess a little higher than 14 should be okay?
 

JVTrain

TFP Expert
Feb 3, 2014
5,081
Central Minnesota
Going over by a couple FC won't hurt anything, just don't over do it. Test and dose as often as every hour when your schedule allows.

# Sent from mobile device. Beware of brevity and spelling errors!
 

chiefwej

LifeTime Supporter
TFP Guide
Jun 12, 2011
3,534
Tucson
If you use Pool Math to determine your target shock level, you will also see a "Mustard Algae Shock" level. If you aren't going to be there to dose the pool you can take the FC up to, but don't exceed that level. That can give you a little extra buffer.
 

LaurenB

Well-known member
Jun 4, 2014
94
Shrewsbury, PA
Thank you.

So last night at 10pm when I got home from work I poured in the amount of bleach pool math told me to.

I didn't get a chance to retest after adding the bleach.

This morning's results were
FC 13
CC 1.5 (down a little from yesterday)

Added 23 oz of bleach to bring it up to 14ppm.

Since I will be gone for 15 hours, I also put in a chlorine puck and left the lid opened a crack, hopefully it will keep the FC up a bit while I'm gone today. Was this a good idea or bad idea?

Thanks for everyone's help!
 

frustratedpoolmom

TFP Expert
LifeTime Supporter
In The Industry
May 20, 2007
12,250
Key West, FL
When you're testing the FC are you sure that you are finished with the FC portion of the test? The water is staying clear for at least 30 seconds? I'm wondering if your FC is higher and you aren't finished with the FC portion when you are adding the drops for the CC portion. (does that make sense?) Make sure the water turns completely clear and stays clear before beginning the CC test. See if that makes a difference. I've never seen pollen cause CC to be that high.

I do agree with using the 10ml sample. No reason for using the 25 mil sample.
 

LaurenB

Well-known member
Jun 4, 2014
94
Shrewsbury, PA
Also, do I need to be monitoring and adjusting my pH during this process? I know adding chlorine raises pH.

- - - Updated - - -

I do make sure it is completely clear, but I don't think I've waited a full 30 seconds before. You think that could be giving me a combine chlorine result that isn't really there?

The water immediately changes back to pink as soon as I add those 5 drops. But a pale pink... Not the electric blinding pink of the free chlorine.
 

JVTrain

TFP Expert
Feb 3, 2014
5,081
Central Minnesota
You're doing just fine with your testing. No need for waiting 30 seconds. In fact, leaving the test sit too long before testing CCs, it will turn pink so the test should be done quickly.

Adding the chlorine puck is not recommended. This will raise your CYA and this point you just need to worry about bleach.

Your pH test is inaccurate when the FC level is 10 or higher, so only test pH if the FC is less than 10 ppm.

# Sent from mobile device. Beware of brevity and spelling errors!
 

LaurenB

Well-known member
Jun 4, 2014
94
Shrewsbury, PA
Do I need to fly home on my lunch break and take the puck out? I'll be late back to work. Or should I just have my husband take it out when he gets home at 6? The canister is only cracked open about an inch.
 

Mr Bruce

TFP Guide
Mar 24, 2014
2,444
Greenville, SC
Your CYA shouldn't change much from a slightly dissolved puck. I use them to remove stains from acorns and such in my pool, but pull them out as soon as the stains are gone, 5-10 minutes.

They are also ok to use on vacation, the point is to get away from using them as your only source of chlorine and to be aware of what they are adding (CYA or Calcium) when you do use them.
 

LaurenB

Well-known member
Jun 4, 2014
94
Shrewsbury, PA
Thank you.

My husband removed the puck and ran a test when he got home.

Results are
FC: 14.5
CC: 1.5

This morning the FC was 13. I put in 23oz 8.25% bleach to raise it to 14.

If I dosed it to raise it to 14, and if the puck dissolved a bit to raise it 14.5... I lost NO free chlorine today?! The pool gets direct sunlight ALL day... and the outside air temp today was 90 - water temp is 80!!

Why is the FC dropping so slowly, and the CC not at all?! What am I doing wrong?!
 

chiefwej

LifeTime Supporter
TFP Guide
Jun 12, 2011
3,534
Tucson
Thank you.

My husband removed the puck and ran a test when he got home.

Results are
FC: 14.5
CC: 1.5

This morning the FC was 13. I put in 23oz 8.25% bleach to raise it to 14.

If I dosed it to raise it to 14, and if the puck dissolved a bit to raise it 14.5... I lost NO free chlorine today?! The pool gets direct sunlight ALL day... and the outside air temp today was 90 - water temp is 80!!

Why is the FC dropping so slowly, and the CC not at all?! What am I doing wrong?!
Nothing, stay with it. It will come down.
 

LaurenB

Well-known member
Jun 4, 2014
94
Shrewsbury, PA
Thanks, Chief. I just want to see some sort of change! Even just the free chlorine dropping a little would make me feel like something is happening.

The instructions with the Taylor Kit say to raise FC to 10x the CC level. If CC is 1.5, should I go ahead and raise to 15?
 

JVTrain

TFP Expert
Feb 3, 2014
5,081
Central Minnesota
Using information on how to care for your pool from multiple sources will always lead to confusion. If you're going with TFP methods, use the documentation and experts here only.

# Sent from mobile device. Beware of brevity and spelling errors!
 

Swampwoman

TFP Expert
LifeTime Supporter
Apr 27, 2012
3,835
Grand Rapids, MI
Welcome!
Did your chlorine-free shock happen to have potassium monopersulphate in it? What was the name of the product?

If so, it could be creating a "false" cc reading. Potassium monopersulfate (a common non-chlorine shock) will show up on FAS-DPD chlorine tests as CC.

Now I realize you had the cc before adding the non-chlorine shock, but if you added any other such product, that could in part explain whats going on here.

This "unintended consequences" phenom is why we advise posters to follow one path or the other, because combining pool store elixirs while engaged in "tested and highly controlled = repeatable results" processes like the TFP slam can confuse the issue a bit.

Let us know the name of what you added, and whether you ever added anything similar before, but keep slamming to see if those ccs can break down.

Cheers!
 

LaurenB

Well-known member
Jun 4, 2014
94
Shrewsbury, PA
I used Leslie's Fresh n' Clear. I'm having a hard time finding the active ingredient online and I already threw the bags away!

But like you said, I had the CC result prior to the non-chlorinated shock.

I'm sorry I'm mixing methods, I'm still new and didn't realize that would be a problem.

We dosed the pool to bring it up to 17.5, since my husband informed me it was actually higher than 1.5... But I'm afraid to take it up to 20!!!!