Huge Chlorine Loss

[garroyo130]

I made the mistake of calculating daily chlorine loss about 2 weeks ago and just adding the recommended amount from that point, every morning. Pool temperature and weather has changed since then, so I'm assuming my needs have changed. Anyhow, we finally got to swim yesterday and I was surprised when I did a chlorine test this morning and found we were at 1.5ppm. I did not test yesterday morning, so I am not sure what the starting point was, but I know that I added 2.5ppm in the morning. I immediately added enough to bring it up to 8ppm (tested 30 min later and confirmed 8ppm). I also tested everything else:

FC: 1.5 (brought up to 8ppm at 6:30am)
pH: 7.8
TA: 80
CH: 350
CYA: 40 (have a sock in there now to get to 50)

I will be doing an OCLT but am wondering if anything else might be using chlorine that I should look out for. We do have a horribly placed Crape Myrtle that has been having me clean the skimmer at least a couple of times a day.

Any assistance is appreciated.

 

[Mdragger88]

Don’t add any more cya until you have the
Overnight Chlorine Loss Test results.
It only makes your potential slam fc level higher.
Average fc loss can be anywhere from 2-5ppm per day- much more than that does rouse suspicion that something may be brewing.
If it is, it looks like you may have caught it early & may be able to take care of it quickly.
Chock it up to a Lesson learned to monitor more closely, it can be tough to anticipate our crazy southern weather!

 

[garroyo130]

Thanks. I've taken the sock out and now have the robot running. I will not add anything until I add chlorine after dark for the OCLT.

 

[PoolStored]

Check the date on your chlorine too?

Chlorine Date Code Decoder - Further Reading

www.troublefreepool.com

 

[garroyo130]

Check the date on your chlorine too?

Chlorine Date Code Decoder - Further Reading

www.troublefreepool.com

I will check the date. I just ordered 12 gal from Walmart and noticed the bottle used yesterday had a different colored cap than im used to.

If the Chlorine was old would it have brought it up to 8ppm still? Does old chlorine just degrade faster?

 

[Mdragger88]

It loses potency as it ages & with improper storage. If you tested & confirmed the addition & the rise was as expected that bottle is fine.

 

[Oly]

It is common in the early summer for daily FC loss to get ahead of pool owners. Many get so far behind that cloudy water is what eventually gets their attention. After a quick test you raised your FC right away, a good response..
Using your test kit to run an Overnight Chlorine Loss Test will diagnose if you have an issue or will put your mind at ease.

 

[clambert1273]

Don’t add any more cya until you have the
Overnight Chlorine Loss Test results.
It only makes your potential slam fc level higher.
Average fc loss can be anywhere from 2-5ppm per day- much more than that does rouse suspicion that something may be brewing.
If it is, it looks like you may have caught it early & may be able to take care of it quickly.
Chock it up to a Lesson learned to monitor more closely, it can be tough to anticipate our crazy southern weather!

Unless you live on the sun like me then my daily loss can be 6-8 easily

 

[garroyo130]

Should I do anything else between now and then? Bump down the pH a notch?

 

[PoolStored]

Should I do anything else between now and then? Bump down the pH a notch?

pH of 7.8 is GREAT. Wait until pH rises to 8, then drop it to 7.6. Any pH in the 7s is just fine....

 

[FlappyLipps]

Unless you live on the sun like me then my daily loss can be 6-8 easily

Whats your CYA?

 

[garroyo130]

Passed test with 0.5 loss, but im guessing I have old bleach. I couldn't find where to read individual pool essentials gallons but 22-361 23:02 B2TX-01 reads to me like December 27, 2022.

 

[Texas Splash]

reads to me like December 27, 2022.

Yes, it's been on a shelf or deep storage for a while Doubtful it was actually 10% at that point.

 

[clambert1273]

Whats your CYA?

Currently too low but normal ride at 80

 

[garroyo130]

Yes, it's been on a shelf or deep storage for a while Doubtful it was actually 10% at that point.

Is there any way to test strength? Or is my best bet to test after adding?

 

[clambert1273]

Is there any way to test strength? Or is my best bet to test after adding?

Best option is just to hunt freshest chlorine on shelves

 

[Texas Splash]

Or is my best bet to test after adding?

I would test again in about 20 - 30 minutes if I was concerned about old chlorine until you go through the old batch.

 

[FlappyLipps]

Is there any way to test strength? Or is my best bet to test after adding?

One drop of 10% chlorine into 500 ml of water should test 10ppm
A water bottle is 450ml which is close enough.

 

[MITBeta]

Is there any way to test strength? Or is my best bet to test after adding?

You can always test the strength of your chlorine by diluting 10,000 to 1 - Put 1ml of bleach in 100ml of distilled water, mix well, then take 1ml of that and mix into another 100ml of distilled water. Then test this mixture with your test kit like normal. Whatever ppm you get as a result is equal to the percentage in your jug.

 

[garroyo130]

Thanks all. Yesterday's chlorine loss was around 1ppm during the day (cloudy all day), so it looks like this issue was caused by lack of testing on my part and possibly old bleach.