I have discovered Chlorine Lock--Please guide me

[sthrndream]

Greetings,
1. 21,000 gallon free form gunite pebble tech pool with spa. Chlorine based. Built in November of 2017 in Middle Georgia.
2. Coming out of winter this year, noticed we were using a high amount of Chlorine tablets....pool turning very light green. What you noticed is that it was slightly cloudy. pH was acceptable (7.7). Decided to use my TFP test kit finally. TA was high (190), FC (2ppm)....and CYA 100.
3. Called pool builder and said run filter (Variable speed pump) at highest setting. In addition, I decided to change out 3.5 inches of water. I ran filter high speed overnight (12 hrs) with no change.
4. Ran CYA test this morning...90-95 ppm. Wife showed me chlorine we had been using....had trichlor and dichlor.
5. Currently draining pool down 3/4ths (3 inches above shallow). Scrubbing side walls of pebble tech as its draining.
6. Will start filling back up this evening.
7. How should I proceed from here on out? I have concerns that my CYA could still be 100 after I fill back up. I know add liquid bleach only, i get that now. I just retired from the Air Force so I have time now . Any comments would be welcome!

 

[mknauss]

No such thing as 'chlorine lock' - that is a pool store term!!

Do you have your own test kit that you are getting those results from?

When you finish refilling and getting the water very well mixed, if CYA still tests at 90 or above, then do the dilution method described in step 8 of CYA test directions.

 

[sthrndream]

Copy no such thing a chlorine lock. My ratio from CYA to FC is 100 to 2 (50:1). Understand ratio should be 7.5:1

I have the deluxe TFP test kit I bought from this site. CYA gave me 100 yesterday and 90-95 today--matches photo. My test yesterday was also validated at the pool store (100ppm).

Will do on last point when pool refilled.

 

[mknauss]

Great on the test kit! Can you add that to your signature? Keeps us from asking all the time.

Be ready to SLAM Process when you get your CYA down. Keep adding liquid chlorine while waiting.

 

[mknauss]

Also, the ratio is not 7.5 to 1. Minimum FC is 5% of CYA, target is 7.5%. See FC/CYA Levels

 

[sthrndream]

Here is how far we drained it down to...now the fill up.

 

[mknauss]

If that does not drop your CYA -- it was very high!!!

Put the hose in the deep end. Better to have it were the water is pooled up.

Good job.

 

[Rancho Cost-a-Lotta]

I wonder what the dogs are thinking...they seem very interested in the progress of the fill.

Nice pool!

 

[sthrndream]

When the pool is filled up:
- I'm going to check the CYA level, if good then I will check and adjust the pH between 7.2-7.5 first with the filter on
- Do I need to take initial readings on FC/CH/TA and CC prior to SLAM?

 

[sthrndream]

Ok Here are my results:

1. FC 1.0ppm
2. TA 100ppm
3. CYA 35ppm
4. pH 7.5
5. CH 125ppm
6. CSI -0.41
7. Temp 79

Recorded at 6 pm Eastern. Pump is running at 3450 rpms constant on.

SLAM Target Chlorine is 14 ppm says to add 2.7 jugs of Kemtech Bleach @10%. I accomplished this.

Will repeat readings in the morning!

 

[mknauss]

How are you testing a FC of 1.01 ppm?

A CYA of 35 ppm is rounded up to 40 ppm. The scale on the vial is logarithmic and thus you can not extrapolate.

You can reduce the pump speed to low.

 

[sthrndream]

How are you testing a FC of 1.01 ppm?

Typo...corrected.

A CYA of 35 ppm is rounded up to 40 ppm. The scale on the vial is logarithmic and thus you can not extrapolate.

copy will increase SLAM to 40 based on logarithm

You can reduce the pump speed to low.
Awesome...thanks!!!!!!

 

[sthrndream]

Morning results:
1. FC 15.0 ppm
2. TA 100 ppm
3. CYA 40 ppm (rounded from 35 ppm due to algorithm)
4. pH 7.6
5. CH unable to get reading. performed twice. 10 drops of reagent then 3 drops to turn it red. It was like pink but then went clear as I was adding last reagent. Could Chlorine level skew this test?
6. CSI -0.32
7. Temp 79

Recorded at 7:24 am Eastern. Pump is running at 1500 rpms constant on.

SLAM Target Chlorine is 16 ppm says to add 27 oz of Kemtech Bleach @10%. I accomplished this.

Will repeat readings in the evening with picture of pool! Would appreciate calcium hardness explanation.

 

[splashpad]

Morning results:
1. FC 15.0 ppm
2. TA 100 ppm
4. pH 7.6
5. CH unable to get reading. performed twice. 10 drops of reagent then 3 drops to turn it red. It was like pink but then went clear as I was adding last reagent. Could Chlorine level skew this test?
6. CSI -0.32

When FC/10+ it reacts with the other test reagents (results invalid)... that being said you do likely have low CH fill water, I would consider upping your CH to at least 200 from your last pre-FC/10+ of CH/125 using PoolMath... Technical FAQs

3. CYA 40 ppm (rounded from 35 ppm due to algorithm)
7. Temp 79

Recorded at 7:24 am Eastern. Pump is running at 1500 rpms constant on.

SLAM Target Chlorine is 16 ppm says to add 27 oz of Kemtech Bleach @10%. I accomplished this.

Will repeat readings in the evening with picture of pool! Would appreciate calcium hardness explanation.

No need to test anything besides FC/CC when FC/10+ Otherwise sounds good. You might want to let your FC drop under 10, then recheck PH & CH. Make sure those are balanced and good to go!
:Note on the CYA: Always use the bigger ten if the soultion is between lines

 

[sthrndream]

Splashpad,

Thanks for the response. I will recheck the CH and every reading once I am done with SLAM. I started last night around dusk. Pool is clearing up. Ill give it at least till tomorrow to ensure the three criteria are met (clarity, OCLT and CC) and will just measure FC and CC.

So based on my limited knowledge, I should tackle bringing the TA down to proper range and then address the low CH assuming all other things are in check?

 

[splashpad]

Splashpad,

Thanks for the response. I will recheck the CH and every reading once I am done with SLAM. I started last night around dusk. Pool is clearing up. Ill give it at least till tomorrow to ensure the three criteria are met (clarity, OCLT and CC) and will just measure FC and CC.

So based on my limited knowledge, I should tackle bringing the TA down to proper range and then address the low CH assuming all other things are in check?

CH should be addressed sooner rather then later (based on your CSI reading in PoolMath)
Recommended Levels - Trouble Free Pool (by surface type)
TA can be addressed over time, unless it is causing rapid PH rise and/or scaling Lower Total Alkalinity - Trouble Free Pool

 

[sthrndream]

Today I took the liberty of updating my signature block that I hope will be more in line with this forum. You can click on my link in my signature and get the latest data.

At 6:39 pm EST, I did a FC and CC. FC yielded 13 ppm and CC 0.0 The pool is still cloudy but getting better. I pressure washed the deck today and thought more organic matter would enter the pool but it didn't. I now have one of three criteria met for successful SLAM and that is the CC, now just need to have more clarity and a successful OCLT.

I hope this will happen tomorrow as I want to tackle the CH.

 

[YippeeSkippy]

Beautiful pool! And thank you for your service, enjoy retirement now!

Have you been brushing the pool daily during the SLAM?? That helps a lot.

Maddie

 

[sthrndream]

Here’s what I have:

OCLT loss of 1ppm from 15-14ppm
CC is 0.0
Clarity is pretty good. Was wondering if deep end could get any clearer. Here is the pic from this am. What do you recommend? Continue SLAM or move on?

 

[duraleigh]

That's pretty darn good. I would let the FC drift on down into maintenance range and maybe run the pump continuously another 24 hours......you might get a bit more clarity but your SLAM is finished. Nice work!