Rapidly Losing Chlorine

poolnj

Gold Supporter
Jun 9, 2013
35
#1
I have been losing chlorine rapidly. These factors are in play: a) The pool is in direct sunlight, b) we have had a heat wave in NJ so the water has been between 88-92 degrees, c) the pool is fairly active and used most of the day, d) my CNY is below recommended levels. I know that the combination is a recipe for chlorine loss, but I am not sure how much.

As an example, I brought my FC Friday evening to 10, no one used the pool Saturday, and the reading Saturday night was less than 1. The black dot on my CNY test does not disappear even with the tube filled, so I know my levels are below 30, just not sure how much.

The other numbers are:
PH: 7.6
TA: 110
CH: 240

The pool is crystal clear but I typically pour in 3 bottles of 121 oz/8.25% liquid bleach each evening and it is depleted in one day.

The recommended CNY levels in Pool School is 30-50, so here are my questions:

1. What number in that 30-50 range should be my target?
2. I am assuming that I need to purchase stabilizer from a pool store to bring up the CNY, but do I listen to them or how much would you guys suggest I add?

Thanks!!
 

jblizzle

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May 19, 2010
41,197
Tucson, AZ
#2
You can get the CYA at Wal-Mart or a big hardware store. I would probably add 20ppm, since you are not sure of the level. Use poolcalculator to determine how many pounds that is.

You may want to do the OCLT to see if you should SLAM the pool since the FC is doing so fast and getting low.
 

duraleigh

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#3
+1 what jblizzle said. I would dose the CYA by adding 20, but don't be surprisewd if your current CYA is quite close to zero so be prepared to add another 20 ppm shortly after the first dose.
 

Butterfly

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May 30, 2007
10,045
South Carolina
#4
CYA, cyanuric acid, also labeled as stabilizer or conditioner. The ingredients on the label should be 96 to 100% cyanuric acid.

CYA is available as a granular and as a liquid. The liquid costs a lot more, and generally isn't worth the extra expense. Granular stabilizer can take up to a week to fully register on the test, so don't retest your CYA level for a week after adding some. Granular/solid stabilizer is best added by pouring it in a sock and placing the sock suspended in front of a return. Give the sock a squeeze occasionally.
 

pwrstrk

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Aug 17, 2012
4,758
Elverson Pa.
#5
Don't forget it will take a couple of days to a week for it to fully register on a test. Just assume its there.


Sent from my iPhone using Tapatalk.
 

poolnj

Gold Supporter
Jun 9, 2013
35
#6
Thanks for all the replies. I did an OCLT and it went from 9 to 7. It was done at 7:30 am and sunrise was 5:46 so not sure if that is still ok even though slightly out of range.

CC is less than .5 and the pool is clear.
 

duraleigh

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#9
I did an OCLT and it went from 9 to 7
Oops, That doesn't quite pass.

I suggest you SLAM the pool. Given your conditions, I think you can likely clear out that little bit of remaining organics in 24-48 hours. It'll cost you a bit of chlorine up front, but you pool will probably be even more clear and your FC consumption will drop.
 

poolnj

Gold Supporter
Jun 9, 2013
35
#10
duraleigh said:
I did an OCLT and it went from 9 to 7
Oops, That doesn't quite pass.
1. Considering that as one reply suggested my cya can even be 0, and the cya chart for 20 cya has a fc target of 10, do I maintain the slam at 10 or less?

2. Can the pool be used during the slam?

3. Do I add my cyanuric acid during the shock and how would that affect my target fc?

4. If my cya is really 0 currently, will a slam even work?
 

pwrstrk

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Aug 17, 2012
4,758
Elverson Pa.
#11
If you have 0 CYA get some in there ASAP. Shoot for 20-30 ppm and assume its there and SLAM according to that level. If you know for sure what your CYA level is SLAM to that level. 0 CYA and shock level FC will be hard on things as the CYA acts as a buffer.

You can swim in FC levels below SLAM levels.


Sent from my iPhone using Tapatalk.
 

DKT113

Well-known member
Jun 28, 2012
336
Butler, PA
#12
poolnj said:
duraleigh said:
I did an OCLT and it went from 9 to 7
Oops, That doesn't quite pass.
1. Considering that as one reply suggested my cya can even be 0, and the cya chart for 20 cya has a fc target of 10, do I maintain the slam at 10 or less?

2. Can the pool be used during the slam?

3. Do I add my cyanuric acid during the shock and how would that affect my target fc?

4. If my cya is really 0 currently, will a slam even work?
1. I believe you should add CYA to get you to the 30-50 range. The lower the CYA the less bleach you will need to SLAM. Your water showing 0 probably does have some in there, a minimal amount. So if you introduce some into the water that will bump you up a bit and will safely protect your bleach and pool as you SLAM. So if you shoot for 30 and you have some in that's no showing you could be at a bit more than 30, but not a paralyzing amount. Remember to test for CYA with back to the sun ~ it does make a difference. Also that once you add the CYA if you go with granular it does take about a week to register so don't test for it, just assume that it is in there. Maybe possibly add 5 to the number you are shooting for so that you take into consideration the CYA in there that isn't showing because it's less than 30 when you test now.

2. It is safe to swim up to SLAM / Shock level chlorine.

3. You add the CYA before beginning SLAM/ shocking process). Once you have added it assume it is in there and SLAM as you would if it actually registered on your test.

4. You need CYA in the pool to SLAM for protection and it also allows you to get the most use out of the bleach you are using.

The experts will pop in here and guide you better. This is my understanding of the SLAM process, which I have been successful with. You will be too ~ just follow what you are told until you learn to pilot the "ship" yourself :)

Good Luck
 

poolnj

Gold Supporter
Jun 9, 2013
35
#13
I'm more confused than ever. Went to my local pool store just now, they tested with a computer and my chlorine came up as 4.5. I tested with my kit as well and sure enough my test is now consistent with theirs at 4.5, which means in 3 hours it went from 7 down to 4.5. Their testing is also showing 25 CYA. That I can't confirm because my test kit only tests to 30 (when my tube is full, the black dot is almost gone though, so that would make sense). If that's the case, would it be algae or similar eating my chlorine and not necessarily, stabilizer? But if so, how come I lose much more during the day; unless algae and sunlight as a combo does more damage?

What is really confusing is that the pool store says my CYA level is fine and I don't need stabilizer, only to add 8 tablets to a chlorinator and let it do it's job. So I feel silly telling them I'm not listening to them and buying stabilizer.

So now that my CYA is 25, considering everything above, what should my target CYA be? (I will save face and go to another pool store to purchase stabilizer :-D )

One I get the answer, hopefully between slamming and raising the CYA, I will be good to go.

(My wife is still not sold on BBB because she says that in the past we used chlorine tabs and a bucket lasted a month, where now we are spending so much on bleach, so why not listen to the pool store. I reminded her that when the pool got cloudy in the past, we started adding clarifier, and every other chemical the pool store can think of at a cost of hundreds of dollars. So I need you guys to pull through with BBB, but at the same time not spending $15 on bleach a day!!)

:cheers:
 

DKT113

Well-known member
Jun 28, 2012
336
Butler, PA
#14
Even without your results your testing will differ from a computer that the pool store uses. That's why the test is so heavily recommended, its results are far more accurate. If you are testing correctly go with your results, they are superior.

You cannot combine Pool Store Methods & BBB Method. They are like Oil & Water and do not mix. You need to select one and go with it. As you have the proper testing devices you are far ahead of the game and completely capable of getting your water balanced. You won't be able to accomplish it though if you try and pick and choose some of the BBB stuff and some of the Pool Store stuff.
 

poolnj

Gold Supporter
Jun 9, 2013
35
#15
DKT113 said:
Even without your results your testing will differ from a computer that the pool store uses. That's why the test is so heavily recommended, its results are far more accurate. If you are testing correctly go with your results, they are superior.

You cannot combine Pool Store Methods & BBB Method. They are like Oil & Water and do not mix. You need to select one and go with it. As you have the proper testing devices you are far ahead of the game and completely capable of getting your water balanced. You won't be able to accomplish it though if you try and pick and choose some of the BBB stuff and some of the Pool Store stuff.
Please see my post just now which shows my results are consistent with theirs. But in general, what is recommended to test CYA under 30 if K-2006's test tube only registers up to 30?
 

duraleigh

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#16
what is recommended to test CYA under 30 if K-2006's test tube only registers up to 30?
Nothing you can do to test lower.

If the test is perfectly clear, you can safely assume CYA is zero. If it's just a bit cloudy, you can guess 15 ppm and then dose based on that.
 

jblizzle

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May 19, 2010
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Tucson, AZ
#17
Don't confuse yourself having the pool store test. Add 20-30ppm of CYA, then start the SLAM process.

Your CYA must be pretty low if you are losing the FC that fast, but that is not unexpected.
 

DKT113

Well-known member
Jun 28, 2012
336
Butler, PA
#18
When you are in the process of SLAM you will use bleach. As your CYA is low it won't be the hit it is for some who SLAM when their CYA is elevated/through the roof.

Once you SLAM and pass all 3 criteria to let it fall ~ provided you maintain a CYA level that allows you the most bang for your buck, your Bleach costs will minimize and then you will not need "additional pool store stuff" to correct when things take a left.

It's going to take her a bit to see the results, if you follow BBB though you will both see results and be thrilled you took the leap of faith.
 

poolnj

Gold Supporter
Jun 9, 2013
35
#19
Leslies sells an "Instant conditioner" in a gallon bottle that they say is a little more expensive but works in 4 hours and will bring my cya to a good level. Should I use that or stick with powder stabilizer?