Zero cya?

[Suley]

Hello all,

I had to leave town as soon as i completed the ascorbic acid test on my pool so I left asking my GF to put polyquat as listed on the bottle to prevent algae. I left with:

FC 0
CC 0
CYA 30
pH 7.2
CH 670
TA 80
Bor 40
temp 82

Last night, upon return (after a week) i saw the pool water was cloudy with little foaming and level had dropped way more than i usually let it but no algae, and tested as:

FC 0
CC 0
CYA did not test
TA 100
PH 7.5
BOR did not test
CH 670
Temp 82F

Added water to bring level up (a bit over 600 Gallons) and, added enough acid to lower pH to 7.2 and chlorine to raise levels to 3ppm. Changed skimmer sock which was chocked. Pump has been running as usual even while i was gone.

Today the tests show:

CYA 0
FC 0
CC 0
TA did not test
BOR 40
pH 7.2
CH did not test
Temp 84F

How can CYA go down to zero when i tested the pool before the ascorbic acid treatment and it was 30? I tested twice to make sure and all chemicals are fresh.

Any help would be appreciated.

 

[JasonLion]

CYA doesn't need to go down all that much to test as zero.

CYA can occasionally be lost when the FC level goes to zero, but that is quite unusual other than over the winter.

 

[PAGirl]

How did you test?

 

[Suley]

I used the TFT 100 test kit for the test.

Could it be that the large amount of makeup water I added yesterday is "helping" in not registering the CYA?

 

[Butterfly]

It could be 'helping'. Remember the CYA test is +/-15 ish. So, if you loose a little while at 30ppm, it could very easily be 20 and not register on the test.

 

[Suley]

Ooo yeah I forgot about that!

Thanks!

 

[Suley]

It has been a week since i used dichlor to raise FC and add CYA to the pool. The pool is still not holding FC. also added pH up (soda Ash) from home depot to keep pH above 7.0 since it was already low after the ascorbic acid treatement.

FC=3.5 overnight drop from 9.0
CC=0.5 overnight drop from 1.0
pH=7.2
CYA=20
TA=130
CH=670
Temp = 84
Borate=40

I know i should add more CYA so should i get CYA powder from home depot or just get a small bucket of dichlor?
The pool is in a sad state with white cloudy water. Should i just add more cya and hope it filters out clear or is a water change becoming necessary?
Any help would be most appreciated!

 

[Butterfly]

Is that an OCLT? Dropped from 9 FC to 3.5 FC? If I read this correctly, you need to SLAM the pool.

But first, let's get a confirmation on the CH.

What is the TA and CH of your fill water?

 

[Suley]

Yes it was an OCLT.

CH is high standing at 670 in the pool.

Tap water:
CH 110
TA 100
Thanks!

 

[Butterfly]

It would be good if you could do a drain/refill dance and get that CH lower.

Also, STOP using Cal-Hypo, as I suspect this is how CH got so high?

For CYA, we recommend using the granular/solid via sock method.

 

[Suley]

I'm not using cal hypo but I think the CH got so high due to high evaporation and almost no splash out due to very little use of the pool.

The drain and refill is coming up as soon as the water rates go down a bit. They are charging us higher "seasonal" rates right now due to the drought.

The pool has cleared up as I slammed it... Now just getting the TA down a bit and wait for a chance to change the water.

 

[Suley]

Thanks for all the help butterfly but today i got a nasty surprise...
I did all the tests using new chemicals and got the following results:

FC=0
CC=0
pH=7.2
TA=150
CH=780
CYA=30
BOR=40
Temp=86F

I have no idea why the CH jumped by a full 100 ppm but i tested twice to make sure. I have no idea why the FC went from 6 to 0 in one day. The water even tastes salty and a bit detergenty perhaps due to the soda ash i added after the ascorbic acid test to raise the pH. All roads are pointing towards a water change.

I calculated to achieve 300ppm CH that I have to replace about 70% of water. I will do so as soon as water restrictions are off in our area. till then I dont want to swim but will have to maintain the pool so that it does not turn into a swamp or becomes a breeding ground for who knows what.

Any recommendations on how to maintain the pool with bare minimum for next few months?

Thanks!

 

[Butterfly]

Get some bleach/liquid chlorine in there ASAP!

Finish the SLAM. You will continue to lose lots of FC until the organics eating it are dead!

You need to test and adjust chlorine levels as frequently as practical, but not more than once per hour, and not less than twice a day.

If you can do one test/adjust in the morning and two in the evening after the sun is off the pool, it should keep you ahead of the green monster and allow you to complete the SLAM, even tho more slowly.

You are testing the CH using the 10ml sample and multiplying drops by 25, right?

- - - Updated - - -

oh, please tell me you have a SpeedStir

 

[Butterfly]

Keep the pH down to 7.2, (but do not test when FC is >10.)

Once SLAM is completed, I suggest you increase CYA to about 50 and maintain FC between 4 and 8, and never below 4.

That should make it smooth sailing until you can get the water changed.

Have you read around here about 'harvesting rainwater' for water replacement?

 

[Suley]

I will do that...

I was using 25 ml sample for the CH test. How do you scale it down to 10 ml? How many drops of each solution do you add? Wow! That would save a lot if reagents !

Yes, thankfully, I do have a speedstir.

I have knowledge about rainwater harvesting and am in the process of designing a system.,. But the issue is no rain in SoCal so I don't expect much out of it.

 

[jblizzle]

The extended test instructions sticky explains it.

But you just use 10 of the first reagent and 3 of the dye and each drop after that to change color is 25ppm.

 

[Suley]

A big thank you!

 

[Butterfly]

I have knowledge about rainwater harvesting and am in the process of designing a system.,. But the issue is no rain in SoCal so I don't expect much out of it.

yep, I believe I remember a song about that

How did the CH test go using smaller sample?

 

[Suley]

Just got home and tested CH with smaller sample it came to be 750.

FC 1.5
CC about 1
TA 150
pH 7.2
Temp 86
CYA 35

Added enough chlorine to bring the level up to 7 ppm and am running the vacuum now. plan to shock it as soon as the sun goes down and will take out the vacuum also. Today at least I had 1.5 ppm FC left as against yesterday when I had 0. I must admit I cant check the pool more than twice a day due to work.

 

[Suley]

Yesterday's readings dont make sense...

at 10PM:

FC 8.5
CC about 0.1 barely pink
pH 7.5

Added HCL to bring pH down to 7.2 and then an hour later:

FC 7.0
CC 0.5
pH 7.2
TA 140

How can FC fall fall so much in an hour?

Shocked the pool and left the pump running overnight.
OCLT showed a loss of FC 3.5 ppm and CC of about 0.75

Cant understand how come the FC and CC are fluctuating so much. Any ideas?