chlorine disappearing

pecker88

Well-known member
Jun 3, 2008
53
Pool size: 25000 - 30000 gal
pebble tech bottom
location: full sun - phoenix, az
floating 3" chlorine tablets <------------------just started using this a week ago
add 1x 96oz jug of bleach EVERY night

For the last 2 summers for the most part, I've ONLY added bleach. Every now and then, I'll lower the PH with "PH Minus". I've noticed at night with light on, the water is a bit cloudy, but only noticeable when looking towards pool light. We also have hard water, but have been noticing heavy calcium build-up around pool rim. Perhaps its just b/c the tile are dark blue?

Morning FC: 5 ppm
Morning CC: 0 ppm

Night FC: 0 - 0.5 ppm
Night CC: 0.5 ppm

Admittedly, I havn't checked CYA for quite awhile; but what would explain what I call, "extreme" loss of chlorine? At this rate, I get 12x 96oz jugs of bleach for $31 and that lasts 12 days, for a total of roughly $80 / month; not to mention the cost of the 3" chlorine tabs. At this rate, it would be cheaper to hire a company to maintain the chemicals; they charge $70 / month.

Just looking for a little advice; thanks!!
 

frustratedpoolmom

TFP Expert
LifeTime Supporter
In The Industry
May 20, 2007
12,179
SWSuburban Chicago, IL
A full set of results, especially CYA would give us a more complete picture and then we can advise you better.

What do you test with?

Where are you purchasing your bleach? Seems rather expensive...

If the pool is uncovered, and your CYA is low, that amount of loss (4ppm approx) would not be unusual for your area. The best way to tell if you have something organic consuming the chlorine is to do an Overnight FC loss test, but you have to use an FAS-DPD chlorine test for it to be accurate.

Now, are you testing AFTER adding the bleach (about an hour) to confirm you are actually reaching 5ppm? And how did you decide 5ppm would be your target (especially if you don't know your CYA level?)

How long have you been using the tablets?
 

pecker88

Well-known member
Jun 3, 2008
53
frustratedpoolmom said:
A full set of results, especially CYA would give us a more complete picture and then we can advise you better.

What do you test with?
Test with TF-?? kit that I bought from this website about 2 yrs ago. The DPD powder is still original (2 yrs old) but the solution is newer, only 1 yr old, (the original bottle ran out). I rarely use the "quick" color matching chlorine test; its too subjective for me...

Where are you purchasing your bleach? Seems rather expensive...
Purchasing boxes of 3x 96oz jugs of bleach at costco - $7.75 / box

If the pool is uncovered, and your CYA is low, that amount of loss (4ppm approx) would not be unusual for your area. The best way to tell if you have something organic consuming the chlorine is to do an Overnight FC loss test, but you have to use an FAS-DPD chlorine test for it to be accurate.
Yes; pool is uncovered. Daily temps are usually 110+ this time of year; full sun.
Will test 1 hr after adding bleach and running pump tonight; then compare with morning test results.


Now, are you testing AFTER adding the bleach (about an hour) to confirm you are actually reaching 5ppm? And how did you decide 5ppm would be your target (especially if you don't know your CYA level?)
No, in my original post, the Night FC/CC test was taken BEFORE adding the bleach
I have not determined a target; I simply add bleach


How long have you been using the tablets?
about 1 week
see replies above
 

frustratedpoolmom

TFP Expert
LifeTime Supporter
In The Industry
May 20, 2007
12,179
SWSuburban Chicago, IL
Walmart has 182 oz jugs for $2.54, something to consider

You need to test after to get an accurate read - the bleach may be being consumed by something as it is added, it may be weakened...

We do need a CYA level. Are you out of reagent?

( I can't read the OTO either :))
 

pecker88

Well-known member
Jun 3, 2008
53
frustratedpoolmom said:
Walmart has 182 oz jugs for $2.54, something to consider

You need to test after to get an accurate read - the bleach may be being consumed by something as it is added, it may be weakened...

We do need a CYA level. Are you out of reagent?

( I can't read the OTO either :))
thanks for the replies!

Good 'ol walmart; thanks for the info, will check this out in my area. That would be almost exactly 1/2 of what I'm paying at costco.

No, still have enough CYA reagent; just havn't done the test.

I'll do the overnight FC loss and CYA tests tonight and report back in the morning.....
 

pecker88

Well-known member
Jun 3, 2008
53
I was wrong in my above posts; I've been adding 1.42 gal of bleach every night, NOT 96 oz. I got the jug sizes/volumes mixed up.

So, at costco, I get 3x 1.42 gal of bleach for $7.75, or $2.58 / jug.
Went to wal-mart last night and 1x 1.42 gal of bleach is $2.54

Added 1.42 gal bleach last night, ran pump for 1 hr, then did DPD chl test and CYA test.
FC = 4.5
CC = 0.5
CYA = 30 - 40

After the pump ran all night, DPD chl test was done again this morning.
FC = 5.0
CC = 0

So, does this explain why I have to add 1.42 gal of bleach every day? I still think that's quite a bit of bleach, like I said, roughly $80 / month. If this continues, I'd be foolish not to get a pool service for $70 / month.

thanks again!
 

frustratedpoolmom

TFP Expert
LifeTime Supporter
In The Industry
May 20, 2007
12,179
SWSuburban Chicago, IL
Well cost wise that makes more sense doesn't it :)

That one jug would raise the FC in a 25,000 gallon pool 3.5 which is about normal for a sunny location with no solar. You have no overnight loss so your issue is not organic.

If you want to use the pool service, by all means try it, but you have to consider what is included in that fee? And does it include chemicals?

You could try it out for awhile and see if it works and if they are able to keep the water sanitary and algae free (I'll admit I'm skeptical...LOL)
 

pecker88

Well-known member
Jun 3, 2008
53
Yeah, pool service includes chemicals; weekly vacuum, ect...best part is that the guy lives across the street. I got his name/number off the side of his truck.

What's the best way to raise CYA?

I know the 3" tri-xxx help, but probably pretty slow?
 

crek31

Platinum Supporter
LifeTime Supporter
Jun 28, 2009
877
Use the pool calculator to figure out how much you need to get to your target and put it in a cotton sock. Tie it in front of the return and let it slowly dissolve into the water. If you want to you can massage it periodically to get it to dissolve faster. It won't show up on a test for a week or so, but it will start working within 24 hours.
 

pecker88

Well-known member
Jun 3, 2008
53
crek31 said:
Use the pool calculator to figure out how much you need to get to your target and put it in a cotton sock. Tie it in front of the return and let it slowly dissolve into the water. If you want to you can massage it periodically to get it to dissolve faster. It won't show up on a test for a week or so, but it will start working within 24 hours.
put about 3 lbs of walmart stabilizer in sock, and like an idiot, tied to return on bottom of pool.

This morning, discovered that the barracuda - zodiac vacuum had swallowed a good portion of the tube sock, tearing a hole in the diaphram! So, tonight, I'm moving it to the stairs in front of a pop-up.

Dont' have any returns on side-walls of pool!

BTW: go HUSKERS! I lived/went to school in lincoln for 6 yrs; nice city!
 
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