Advice please! Can’t maintain FC level or pass overnight test.

[blueskyup]

I'm glad to be starting my first year using the TFP Method!! In short, last season I closed the pool with high CYA issues/problems with maintaining FC and my plan was to open it up in 2018 and do a 75% drain and refill. The issue I had last year was I couldn't maintain an FC level so the pool store had me using chlorine that had trichlor in it to shock. In addition, I was using the pucks that had trichlor in them. This did havoc to my CYA and even more to my wallet. I was never aware of the effects of CYA on chlorine until I visited this site. I came to this Forum at that time to see what I can do and it was recommended I just call it a year and start over in 2018. Flashforward to now:

I opened our pool beginning of May and did the re-fill. I successfully got the CYA down to 45. Once I achieved this my plan was to SLAMM it so it was ready for the summer. I started this on May 12th and since haven't stopped. I have maintained an FC level of around 18 and the water is pretty clear. The only item I am having issues is sustaining the FC level and I can't pass the overnight test. I have read this can take some time but I just want to see if anyone has any pointers and can verify I am doing this the right away. I have vacuumed the pool completely, scrubbed sides, clean lights, skimmers/flaps, and washed our steps. Once I had everything vacuumed I took the filter out and put a clean set in. I am using a taylor K-2006c test kit. I also have a Vinyl cover so during the day I should not have any loss from the sun. Here are my numbers since I started. Once I complete the Slamm I will deal with PH and TA. Any help is appreciated - THank you!


May 12 @ 6pm
Added 20l liquid chlorine
FC 4.2
CC .4
PH 8+
TA 170
Added 15l LC

May 12 @ 8:20
FC 16
CC 1.5
Added 5L LC

May 13 @ 10:20
FC 14.5
CC 1.5
CYA 45
Add 10l Liquid chlroine

May 14 @1
FC 14
CC1
TA 150
PH 8
CH 190
SI .25
Added 5l LC

May 14 @8pm
FC 16.5
CC 1
Added 6L bleach


May 15 @ 12pm
FC 16
CC .5
Add 5l LC

May 15 @ 9pm
FC 18.5
CC <.5 (barely turned red)
Overnight test
Pool vacuum / cleaned filter

May 16 @ 8am
FC 15
CC <.5
Added 2.5l LC

May 16 at 7pm
FC 14
Cc .7
7.5l LC
Pool Vacuum
Put clean filters in

May 16 at 10pm
Fc 18.5
Cc .5
2.5l LC

May 17 at 12pm
Fc 16.5
Cc .5
Added 2.5L LC

May 17 @8PM
FC 18.5
CC .7
CYA 45
Add 3l LC

May 17 @ 10:30pm
FC 22.5
Cc .5
Overnight test

May 18 @ 5am
Fc 19
Cc 0

May 18 @12:47pm
Fc 17.5
CC .5
Added 3L LC

 

[kellyfair]

CYA is measured in 10s, so you should round your 45 up to 50. With a CYA of 50, your SLAM level is 20. I would guess that is the reason you haven’t been able to get over that final hurdle.

 

[mknauss]

Welcome to the forum!

You cannot measure a CYA of 45. The vial is in logarithmic scale. So you round up to the next full 10. So 50 for CYA. That makes your shock level 20 ppm FC. you need to maintain that as often as possible.

No need to test anything but FC until your water is clear. Really Clear. Then you can try the OCLT. pH is meaningless at FC above 10.

Keep it up.

Take care.

 

[blueskyup]

Thank you,

When I measured my CYA I got to the 40 mark (I could still see the black dot but barely). I decided I would go in between to cover myself as I didn’t know if I was readin the cya test correctly. Since then I did research on here and confirmed that the 40 reading would be correct.

I have done another and confirmed the cya is 40.

this said, should I proceed with maintaining an fc of 20? Thank you for the continued advice.

 

[rolo918]

Yes if your cya is around 50 then FC 20

 

[blueskyup]

Hi Guys, checking in with an update. I confirmed CYA is 40.

Here are are my results from the past few days. I did an overnight loss test last night and appeared to pass. However, based on the results during the day I’m not so sure. I added 2L of Chlorine this morning and still went down by 1ppm. Do I keep up with the Slamm or am I complete? I do have a vinyl cover and shouldn’t have loss from the sun during the day. Water is clear. I plan to to another vacuum tomorrow and rinse the filters again.

Thank you!



May 21 @ 930pm
FC 22.5
CC .5
Overnight test


May 22 @8am
Fc 19
cc .5
Added 2.5l LC
Failed overnight


May 22 @1230pm
Fc 21.5
cc .5


May 22 @8pm
Fc 19.5
Add 2.5l LC


May 22 @10:10pm
FC 22
CC .5
Overnight test


May 23 @9am
FC 21
CC.5
Overnight pass
Added 2L LC


May 23 @7pm
FC 20
CC .5

 

[kellyfair]

I think I might be missing something... today, did you test between 9am and 7pm? When you added the 2 liters at 9am, what FC were you shouting for?

 

[blueskyup]

Since I just sneaked past the over night test I decided I would keep the slamm up for one more night. I wasn’t able to come home for lunch today so I figured I would add the 2l in the morning to make sure the FC was maintained until I got back at dinner. My assumption in the morning was that if I added the 2l my FC would be higher when I got home, but the opposite happened.

 

[kellyfair]

Did you test after the two liters to see where that took you?

 

[kellyfair]

If the pool size in your signature is correct, 2 liters of 10% would have only raised your FC by 1-2 points. So, when you tested it 10 hours later, it would have dropped at least a little, since you are still fighting something in your water.

Why are you running your FC so high? If your CYA truly is 40, your SLAM level is 16.

 

[blueskyup]

I didn’t test 2 hours after as I was at work and couldn’t get home for lunch.

I was not sure if I should continue with the slamm even though it appeared from the overnight test I had passed.

I did another overnight night test last night and I lost 1ppm. I haven’t added anything to the pool and will check it at lunch again. I’ll post the results then.

 

[blueskyup]

Here is an update from yesterday. I thought I had passed the finish line last night as my daily FC values stayed rather constant. However, I failed the overnight test when I checked this morning. I’m not sure where to go from here as I have passed the overnight test once and then failed a few days later. I’m approaching the 2 week mark of slamming. Any advice is appreciated.

May 23 @7pm
FC 20
CC .5


May 24 @800am
FC 18.5
CC .5


May 24 @1pm
FC 18
CC 0


May 24 @930pm
FC 18


May 25 @8am
FC 16.5
Cc 0

 

[pypeke]

I am NOT one of the experts.....

Next time, get test and adjust TA and pH BEFORE you SLAM.

Is it possible to test earlier in the morning? You have been testing at 8:00 and 9:00 a.m.

I'm in Oklahoma so I test around 6:00 a.m. If I tested OCLT at 8:00 or 9:00 a.m., it would show that I lost more chlorine than I did.

Not sure where you live so I don't know if that will help you or not.

It's the weekend so maybe you can test more often, keep FC at your correct level, test FC after dark, add chlorine if needed and retest, and maybe test earlier in the morning.

I spent an entire month fighting my pool last year so I feel your pain.

This year, I put a safety cover on my pool in November. Starting in March, I began checking the pool color once a week. In May when I was ready to start SLAMing, I took the cover off and the water was still clear. I know it had contaminates in it, but it was not green! Usually by April we have snakes, frogs, and thousands of tadpoles. Frog skeletons were in my pool skimmer basket. Two or three days of SLAMing, and I was done. We had that cover for five years, but I couldn't get my husband to drill the holes in concrete so I could install it. Gentle persuasion and begging (nagging & ultimatums) finally got it installed. Weeks of me scrubbing and brushing the pool and $$$$ in bleach for five years and a cover was worth the price. Good luck!

 

[pypeke]

I went back to read the dates and times you tested and adjusted. On the 13th, you only checked 1 time. On the 12th, 14th, and 15th you tested/adjusted twice a day. So my opinion is that you didn't spend enough time testing or adjusting, but they could have been work days. (So you had to start SLAM all over again!)

On the 16th and 17th, you checked 3 times. So when you did the OCLT test on 17th/18th, you failed the OCLT because you still had contaminates. You tested early at 5:00 a.m. on the 18th. Yay! Not sure what happened on 18th- 21st????? Then you started SLAMming again on the 21st. You were so close!

I do not consider my SLAMing is done until I get 0 loss of FC early in the morning. No squeaking by for me.

I would suggest you test and adjust VERY often this weekend and MAYBE you will pass the OCLT. Don't forget that after you add chlorine (per pool math calculations), you have to retest as soon as that chlorine has been circulated. Don't assume that the amount of chlorine that you put in your pool at the target FC in the morning will automatically reach the target FC by afternoon. (Don't wait until hours later to test FC after you have added chlorine.) Sunlight is eating it up too, and you don't know for certain that your pool actually REACHED the target FC after you added the chlorine. It is possible that you have not stayed at your target level long enough to kill all of the contaminates. You cleaned steps, light, etc. so I don't know what else it could be.

Just a thought....When you are collecting your sample for testing, are you submerging an upside down container in the deep end ALL the way up to your elbow? Then turning the container right side up so it fills with water that is NOT from the surface of the pool? (I wish I had a giant 3 ft turkey baster!)

Others are right about your FC target. I know you were at work and wanted to leave extra chlorine in since you couldn't be there, but maybe there is a saturation limit???? I know that when I used granular shock, there was a saturation limit and not all dissolved in the bucket. I had to pour some of the water out and add fresh to get the rest to dissolve. You might ask Chem Geek about that. Otherwise you are just wasting chlorine and money if there is a saturation limit.

Also, check the dates on your chlorine bottles. What percentage are you using? Plain bleach, right?

I am soooooooo NOT an expert!

 

[blueskyup]

Thank you guys for your comments, it is my first time doing this so I will be taking all your recommendations. In my recent posts, you made note of my testing being not regular during Slamm. I did not post all the results for those days. To assist I have copied my results each day I started the Slamm. I will admit my testing is not frequent. I work during the day so typically I try to do it in the am, noon and dinner and just before bed. During the Slamm period, I have maintained Slamm FC levels the based on my CYA (40). I am using Liquid Chlorine (10.8%).

I feel I have hit a roadblock if I should proceed or stop. The night I passed the overnight test and the day where my FC only dropped by .5 made me believe I had passed. However, when I attempted to do the test again it failed. I wonder if Chemgeek can comment on the Saturation theory? I would hate to be wasting chlorine.


I live in Central Canada so we have pretty warm summers and then shut things down for the winter. I do have a vinyl cover on my pool so this should protect it from sun loss. That is why I haven't testing at 6am vs. 9am. For water samples, I have been doing as you suggest. However, I only get about elbow deep. In less than 2 weeks I already finished the 2 oz reagent for the FC test. I had to order another one, in Canada, it is not cheap.

This weekend I will do as you suggest and hopefully get through this. If anyone has some knowledge they would like to share based on the additional info, please do. The pool looks amazing though!

May 12 @ 6pm
Added 20l liquid chlorine
FC 4.2
CC .4
PH 8+
TA 170
Added 15l LC

May 12 @ 8:20
FC 16
CC 1.5
Added 5L LC

May 13 @ 10:20
FC 14.5
CC 1.5
CYA 40
Add 10l Liquid chlroine

May 14 @1
FC 14
CC1
TA 150
PH 8
CH 190
SI .25
Added 5l LC

May 14 @8pm
FC 16.5
CC 1
Added 6L bleach


May 15 @ 12pm
FC 16
CC .5
Add 5l LC

May 15 @ 9pm
FC 18.5
CC <.5 (barely turned red)
Overnight test
Pool vacuum / cleaned filter

May 16 @ 8am
FC 15
CC <.5
Added 2.5l LC

May 16 at 7pm
FC 14
Cc .7
7.5l LC
Pool Vacuum
Put clean filters in

May 16 at 10pm
Fc 18.5
Cc .5
2.5l LC

May 17 at 12pm
Fc 16.5
Cc .5
Added 2.5L LC

May 17 @8PM
FC 18.5
CC .5
CYA 40
Add 3l LC

May 17 @ 10:30pm
FC 22.5
Cc .5
Overnight test

May 18 @ 5am
Fc 19
Cc 0

May 18 @12:47pm
Fc 17.5
CC .5
Added 3L LC


May 18 @ 530
FC 19
CC .5
1l LC


May 19 @930am
FC 21
CC.5


May 19 @2:40pm
FC 19.5
CC .5
1l LC

8:00pm
Added 1l LC

May 20 @10am
Fc19
Cc.5
Added 1l LC

May 20 10:45
Added 1l LC
FC 18.5
Cc .5
Overnight test

May 21 @10am
Fc 17
Cc.5
Did not pass
5l LC


May 21@8pm
Vacuumed pool
1l LC 7pm
Fc 19.5

May 21 @ 930pm
FC 22.5
Overnight test

May 22 @8am
Fc 19
Added 2.5l LC
Failed overnight

May 22 @1230pm
Fc 21.5

May 22 @8pm
Fc 19.5
Add 2.5l LC

May 22 @10:10pm
FC 22
CC .5
Overnight test

May 23 @9am
FC 21
CC.5
**Overnight pass
Added 2L LC

May 23 @7pm
FC 20
CC .5


May 24 @800am
FC 18.5
CC .5

May 24 @1pm
FC 18
CC 0


May 24 @930pm
FC 18
**Maintained FC during day

May 25 @8am
FC 16.5
Cc 0

 

[pypeke]

yes, that's what I thought when I said it was probably because of work days. Nothing you can do about it, but you are really trying by going home at lunch time! Good for you.

I only had the days you had listed to make an opinion so I am glad you posted the rest.

The cover should stop chlorine loss, but I was just suggesting testing earlier in the day to rule out loss of FC through sunlight (even with a cover).

This is a head scratcher, but I think you are doing everything right. I have mentioned what little I know...production date on bleach bottles, getting a deeper water sample, checking that your FC went back to your target FC half an hour after you added bleach, etc. The only thing I can think of is if the bleach was kept in the heat at the store and turned to water. But, I am sure you would have noticed if that awful bleach smell was missing!

Try again tonight for the OCLT. Maybe you did pass it already. If so, your FC can drift down so you can swim. I can't remember if you said whether your pool was clear or still cloudy (or not sparkling). That part of the SLAM always holds me up.

You are done when:

• CC is 0.5 or lower;
• You pass an OCLT (ie overnight FC loss test shows a loss of 1.0 ppm or less);
• And the water is clear.

It looks like you have passed the first and second one.


Hang in there! You are doing well.

 

[blueskyup]

The water is very clear. I passed the overnight test one night but failed the following. My predicament is if I should keep going or not as it seems I passed the slamm requirements to pass. As pypeke mentioned, maybe I need to go until I have 0 change in FC for the over night?

The odd thing is i am able to hold FC during the day but lose it at night. Yesterday my FC was 16.5 at 8am and 16.5 and 11pm. Overnight I lost 1.5.

I am going to do another vacuum today and clean the filters out. I’ll do some more frequent tests and either post them end of day or on Sunday.

 

[mknauss]

Are you leaving your pump run overnight during the OCLT? It makes no sense to have 0 FC drop during the day but some overnight.

 

[pypeke]

I wish I had your pool cover since it keeps your FC in. I lose a lot during the day. Which cover do you have, if you don't mind sharing that information?

I see that you have 110,000 liters listed in your signature. Where is Regina? Could where you live play a role in the problem? What I mean is that maintaining pools in Florida is different than pools in Canada. I am grasping at straws...

 

[pypeke]

I found this thread about OCLT and covers.

OCLT with cover