Low Cya and high Fc

[tyrelrobert]

We had a VSP put in about 2 weeks ago but when our pool guy did it, between storms and his busy schedule, the pool wasn't circulated for about 4.5 days. Of course the water has been cloudy since then. Before finding tfp I was only using the test strips.

They have consistently been showing very low Cya but higher free chlorine. After adding 4 lbs stabalizer( his recommendation) the water has gotten clearer but it isn't crystal clear yet. The levels are still the same according to the test strips.

My 2006c water tester is scheduled to be delivered today so I can properly test and do this myself going forward. Is there anything i should do to get ready? I have liquid chlorine on hand ready to slam. Should i turn off the SWG? I will post the test results as soon as I can.

Thanks for any advice

Tyrel
Omaha,NE

 

[mknauss]

Welcome to the forum!
Post your test results. I would suspect you will need to follow the SLAM Process so give that a read.
I suggest you read through Pool Care Basics - Trouble Free Pool and even look at a few of our videos TFP-TV - Trouble Free Pool

 

[tim5055]

Welcome to TFP

Step one will be an overnight chlorine loss test. This will tell us if bad stuff is growing in the water. For this test yes, the SWCG must be off.

That you say the water is cloudy tells me the stuff is growing and you will probably have to SLAM your pool.

Perform the Overnight FC Loss Test (OCLT)

The Overnight Chlorine Loss Test tells if the SLAM is finished or if you need to start a SLAM. This article says how to do the OCLT.

www.troublefreepool.com

SLAM - Shock Level and Maintain

We’ve all had to deal with a green pool. Clear algae from your pool with a SLAM! Read here to use shock level and maintain to clear your pool.

www.troublefreepool.com

Now, you mention a "pool guy". Will he be caring for the pool or you? We have very different methods of pool care that may not match his.


How much Pool School have you read? Start with these:

ABC's of Pool Water Chemistry

There are several items things every pool owner should know about swimming pool water. We share details on the basics of Pool Water Chemistry.

www.troublefreepool.com

Recommended Pool Chemicals

Which should I buy? TFP's recommended pool chemicals are cheap, easy, and won't unbalance your pool water.

www.troublefreepool.com

The Free Chlorine and Cyanuric Acid Relationship

Managing your cyanuric acid and Free Chlorine levels is key to stabilizing your pool. Learn how these two items affect each other.

www.troublefreepool.com

 

[tyrelrobert]

Welcome to TFP

Step one will be an overnight chlorine loss test. This will tell us if bad stuff is growing in the water. For this test yes, the SWCG must be off.

That you say the water is cloudy tells me the stuff is growing and you will probably have to SLAM your pool.

Perform the Overnight FC Loss Test (OCLT)

The Overnight Chlorine Loss Test tells if the SLAM is finished or if you need to start a SLAM. This article says how to do the OCLT.

www.troublefreepool.com

SLAM - Shock Level and Maintain

We’ve all had to deal with a green pool. Clear algae from your pool with a SLAM! Read here to use shock level and maintain to clear your pool.

www.troublefreepool.com

Now, you mention a "pool guy". Will he be caring for the pool or you? We have very different methods of pool care that may not match his.


How much Pool School have you read? Start with these:

ABC's of Pool Water Chemistry

There are several items things every pool owner should know about swimming pool water. We share details on the basics of Pool Water Chemistry.

www.troublefreepool.com

Recommended Pool Chemicals

Which should I buy? TFP's recommended pool chemicals are cheap, easy, and won't unbalance your pool water.

www.troublefreepool.com

The Free Chlorine and Cyanuric Acid Relationship

Managing your cyanuric acid and Free Chlorine levels is key to stabilizing your pool. Learn how these two items affect each other.

www.troublefreepool.com

I will be doing it going forward. I have been reading through everything the past couple days so I am getting my knowledge base built.

 

[tyrelrobert]

Alright test kit came and here is the initial results so far. I haven't ran all tests yet but i will try to eventually.

Ph - 7.8 or 8 i will retest but those were hard to differentiate
Cya- 70 i will retest but that surprised me as the test strips always said low
Fc - 13
Cc- 2

I will run the fc and cc test again at end of day so i can do the overnight test.

My question now is do I start the slam or wait until the overnight test is done? I'm sure with the cc being a 2 a slam will be recommended. I bought a case of 12.5% liquid chlorine if it is recommended.

Thanks for all the insight

 

[wireform]

Hi and welcome. Your Ph unreliable above a FC of 10 and for slam it would need to be lowered to 7.2
The CYA will make the slam a bit expensive causing you to need more chlorine. Do a OCLT and lets see what the morning level is first. Was the pool covered and uncovered just before testing as that can cause a higher CC before it out gases itself.

 

[Mdragger88]

Tip For the ph test - using a white background is helpful- i often use my phone’s browser (open to tfp of course )
The cya result is not that surprising that its so different than a guess strip as they are often bleached out by higher fc levels.
You can lower ph to 7.2 & begin the SLAM Process if u wish & forego the oclt as u meet the criteria w/ the cc’s.
You will need to know your ta to lower your ph correctly.
Use PoolMath for calculating additions.
SLAM ON

 

[tyrelrobert]

Pool was not covered. We had some rain today but that is about it.

 

[Mdragger88]

Good catch on the ph @wireform

 

[Rancho Cost-a-Lotta]

You're getting bombarded with info right now...sorry, here comes another bomb.

Do this first so we're all on the same page. The calcium hardness test may be relevant if your pool has a plaster finish.

Create Your Signature - Further Reading

www.troublefreepool.com

 

[wireform]

Also be sure the CYA is what it is. When you slam per 70 it will use X amount but if it's actually lower the FC above the true CYA level will burn off quicker and wont hold well. Being this is a first at testing you may want to double check it.

 

[wireform]

You're getting bombarded with info right now...sorry, here comes another bomb.

Do this first so we're all on the same page. The calcium hardness test may be relevant if your pool has a plaster finish.

Create Your Signature - Further Reading

www.troublefreepool.com

it's a vinyl.

 

[tyrelrobert]

Tested everything again about 1030 pm.

Ph was around 7.8 i think the dry acid i added was bringing it down.

Ta was high at 130
Fc was 10
Cc was down to 1
Cya 70
I will test the chlorine and ph again at 530 to see what we have going on

 

[PoolStored]

Tested everything again about 1030 pm.

Ph was around 7.8 i think the dry acid i added was bringing it down.

Ta was high at 130
Fc was 10

Cya 70

1) If your FC is 10 or greater, your pH test will not work. You need to be below FC 10.
2) TA may be a bit high, but I would manage your pH to be in the 7s and manage that. Your TA will come down over time.
3) You cannot test an accurate CYA when you do not have sunlight (10:30pm) This is a particulate test. Get some really good sunlight and test again...

CYA - Cyanuric Acid Test

Cyanuric Acid (CYA) is the chemical name for what is commonly referred to as Stabilizer … Read more…

www.troublefreepool.com

 

[tyrelrobert]

I'm guessing I had a testing error last night because the fc was back at 13.5 and cc was 0.5 this morning. I will keep doing the overnight tests but in the meantime do I wait for some sun to do the cya test and then start slamming? Ph was down around 7.5. Added some more dry acid to try to lower it a bit more.

 

[PoolStored]

I'm guessing I had a testing error last night because the fc was back at 13.5 and cc was 0.5 this morning. I will keep doing the overnight tests but in the meantime do I wait for some sun to do the cya test and then start slamming? Ph was down around 7.5. Added some more dry acid to try to lower it a bit more.

Yes, you want bright sun at your back. Re-read the link above. Slam away! I would stay away from dry acid as it adds sulfates to the pool, better to use muriatic acid. Sulfates will build up in the water and destroy metal.

 

[x Wild Bill x]

I'm guessing I had a testing error last night because the fc was back at 13.5 and cc was 0.5 this morning. I will keep doing the overnight tests but in the meantime do I wait for some sun to do the cya test and then start slamming? Ph was down around 7.5. Added some more dry acid to try to lower it a bit more.

Also, as mentioned above, the pH test is not valid when FC is above 10. I would not adjust the pH until the fc drops below 10 and you get a true pH reading. A low pH is much more damaging to pools and equipment than high pH.

 

[tyrelrobert]

Alright, day 1 of slamming almost done. After reading about mustard algae i am pretty sure that is what i am dealing with. I have been seeing "loose dirt" on the steps and corners for awhile which i thought was pollen or just dirt. At least i have been brushing religiously but now i will really brush it all.

I have kept the fc up most of the day and actually between the last 2 checks it basically didnt drop (hoping thats a good sign)

I will check 1 more time to start the overnight test and hopefully see some improvement in the morning.

 

[tyrelrobert]

Morning reading for overnight test the fc only dropped by 4 ppm and cc by 0.5.

Added more chlorine to get to slam level.

Water still looks cloudy but there wasnt any sediment on the steps or edges like in days past. Brushed and ran the prowler. Hoping to see a small improvement by days end.

 

[Texas Splash]

Stick with it. Any progress is a good thing. Maintain the FC level, do the normal brushing, and inspect any/all potential hiding areas for algae. The chlorine will do the rest.