Bleach Usage

jasonknox

Platinum Supporter
May 4, 2010
300
SW Georgia
Right now in the summer months I have to add 182oz. of bleach daily to keep my pool at a FC of 6 or greater. Does this sound reasonable? I know that increased CYA will raise the amount of bleach I use to shock the pool, but will this reduce the amount of bleach that the sun burns off daily thus enabling me to use less bleach on a daily basis?

FC 6.5
CC 0
CYA 50
TA 110
PH 7.5
 

Bama Rambler

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2009
22,958
SouthWest Alabama
That's only 2.5ppm per day loss in a pool your size so that's not bad. Raising your CYA to 60 might help a little. I wouldn't og much higher than that though.
 

h2ctpdjl

LifeTime Supporter
Jul 12, 2008
251
Indiana
I add 111oz 6% chlorine each day. Pool is in the hot sun all day long (water temp 90). I keep my CYA level at 40, so my Min FC level is 3, with a target of 5. With my 3ppm loss each day, I add 7ppm each night so that my FC level does not go below 4 each day. So far, so good.
 

svenpup

LifeTime Supporter
Nov 18, 2009
835
Sacramento, CA
h2ctpdjl said:
I add 111oz 6% chlorine each day. Pool is in the hot sun all day long (water temp 90). I keep my CYA level at 40, so my Min FC level is 3, with a target of 5. With my 3ppm loss each day, I add 7ppm each night so that my FC level does not go below 4 each day. So far, so good.
h2ctpdjl, I think you meant "I add enough to reach 7ppm each night so that my FC level does not go below 4"
 

257WbyMag

TFP Expert
LifeTime Supporter
Feb 23, 2008
5,061
Denton, TX
That sounds right to me. I also have a close friend who has a 35K gallon pool and that is exactly what she adds to her pool every day in the summer.
 

TimS

LifeTime Supporter
Sep 21, 2009
214
Central Missouri
I'm further north than you, (so you would expect less intense UV reactions.) My pool is in direct sunlight from about 1 hour after sunrise until early evening. (Yesterday that would have been about 7:00a - 6:30p) The only trees are 75' to the east, and the only other source of shade is the house on the west. My CYA is 70-75, the water temp is 83-85, and I lose between 3 and 4ppm FC (3-4 qts, in my 13K,) every day if the pool is uncovered. If the pool is covered, my FC loss is closer to 2-3ppm per week, or less than 0.5ppm per day.

That seems like a high loss due to sunlight to me, too, but it's what I consistently see.
 

JTS

LifeTime Supporter
May 25, 2010
30
Does anyone feel weird getting a couple of shopping carts full of bleach at the store every month?????

Maybe its just me.
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,082
San Rafael, CA USA
TimS said:
My CYA is 70-75, the water temp is 83-85, and I lose between 3 and 4ppm FC (3-4 qts, in my 13K,) every day if the pool is uncovered. If the pool is covered, my FC loss is closer to 2-3ppm per week, or less than 0.5ppm per day.
That's interesting Tim. This does seem a bit higher than usually seen, especially at the higher CYA level. So do you bounce between 10 ppm and 6 ppm or 9 ppm and 6 ppm FC or something like that? What is the depth of your pool, both shallow and deep ends (if it has both)? Your loss with the pool covered is exceptionally low. In my pool if there is no bather load and the pool is covered the daily chlorine use is around 0.7 ppm FC per day, but this is at warmer 88ºF temps. If the water gets closer to 80ºF then the chlorine usage drops considerably by almost half.
 

dmanb2b

TFP Expert
LifeTime Supporter
Apr 4, 2009
3,734
NY
If I'm at wally's...especially at night, there are not many sights that appear weird :goodjob: To help on the amount of jugs folks are lugging an alternative is to switch to 12.5% liquid chlorine or get a swg.
 

TimS

LifeTime Supporter
Sep 21, 2009
214
Central Missouri
chem geek said:
That's interesting Tim. This does seem a bit higher than usually seen, especially at the higher CYA level. So do you bounce between 10 ppm and 6 ppm or 9 ppm and 6 ppm FC or something like that? What is the depth of your pool, both shallow and deep ends (if it has both)? Your loss with the pool covered is exceptionally low. In my pool if there is no bather load and the pool is covered the daily chlorine use is around 0.7 ppm FC per day, but this is at warmer 88ºF temps. If the water gets closer to 80ºF then the chlorine usage drops considerably by almost half.
I originally had my CYA at around 45-50 (I'm never quite sure where that dot completely disappears. If I stare at it long enough, it often seems to come back. :) ) and I was losing about the same amount at 75 degrees. I ramped the CYA up to try to lower the demand, but at the same time the temps went up, so it stayed roughly the same. My 0.5ppm/day loss with the pool covered is actually a few weeks old, when the air and water temps were a bit cooler. DW and kids use it fairly frequently, but not every day. I haven't had it covered for a week at a time since the beginning of May, so my current demand in that situation may be a bit higher right now. If it stays covered for a day, I often won't test that day, since I know it's not going to drop below my minimum level.

Yes, it's bouncing between 10-6 or 9-6. In a purely unscientific observation (not even a deliberate test,) over the past couple of days, I raised FC from 6 to (supposedly) 10 on Monday at around 4:30 pm. Left the pool uncovered until about 6:30p (about the time the sun went behind the house, and the pool was in full shade.) I covered it, and it remained covered all day Tuesday and again all morning and early afternoon Wednesday until about 3:00pm, when it is still in full sun. During that time, we got about 1/8" rain, and a couple of worms in the pool. (I still want to know how I get worms in an above ground pool. I've even gotten them with the winter cover on, so it can't be birds!) At 8:00pm, Wednesday, FC was back down to 7.0. The water temp at that time was 87. That drop seems to be bit high for having the pool uncovered only 7 hours and only 1/8" rain, but I've never tried to keep track of how much I lose during any given time. (i.e. so much from 6am-9am, so much from 9am-12pm, etc.) It's still only a 3ppm drop over more than 48 hours.

I'm using WalMart "Great Value" 6%. I have no real reason to think it is incredibly old, since they do go through a lot at the store. On the other hand, I'm basing my upper level on the amount I've added - its been a while since I actually tested after adding bleach to see what level I'm really hitting. It's possible that I'm off a bit, but probably not much. The last time I tested after adding, I was off by less than 0.2ppm. I do actually measure the amount I'm putting in using a graduated pitcher marked off in pints, so I'm always within a couple of ounces of my target. According to the pool calculator, in my pool 1 quart of 6% is a gain of 1.1ppm, and one gallon is 4.6ppm.

I don't have a deep end, but the center (round pool) is about 2" deeper that the sides. The sides are normally about 47" and the center is normally about 49". We've had several inches of rain over the past week, and I haven't drained it back down yet. Between rain, evaporation, and splash out, my net water gain over the past couple of weeks has been 2-1/2", so I'm a bit high right now. The FC demand has remained pretty constant since the beginning of May. If the pool is uncovered, the demand is going to be between 3-4ppm/day. If the pool is covered, it's significantly lower.

I've done all my calcs on a uniform depth of 48". It's been a while since I actually measured the depth, but it's pretty close to that.

I also don't have any reason to think I have any organics beyond the occasional bug or worm, since my FC loss with the pool covered is so low. The water is also very clear, so no indication there. I haven't actually done an overnight test, simply because I haven't had any indication that I need to. I probably should, just to be sure.
 

TimS

LifeTime Supporter
Sep 21, 2009
214
Central Missouri
Wednesday at 8:00pm, I dosed the pool to an FC of 10, (high side for my CYA of 70) and put the cover on. The water was around 87° at that point. The cover remained on overnight and all day Thursday. I tested again at 4:30 Thursday afternoon, and had an FC of 9.0 and a water temp of 91°. So had a drop of 1ppm instead of the 0.5 I was seeing with the pool covered and at lower temps at the beginning of May. The pool stayed covered until 7:30p after the sun was completely off the pool. DW and I swam for about an hour, and I left the cover off overnight (91° is too hot to be refreshing.) This morning, at 6:30a, before the sun hit the pool, water temp was 87°, and FC was still 9.0, so no organics. I didn't put the cover back, so predict I'll have an FC of 5.5 - 6.0 this evening. It's supposed to be a mostly sunny, hot day with highs in the lower 90's, with a chance of late afternoon showers.
 

ffly

Member
Jun 18, 2010
11
Hello! Noooobie here.

Hi TimS, is FC 9.0 too high to swim in? I read only FC below 4 is good to jump in...

Bama Rambler, How do you convert fl ounce to ppm? 182 fl oz = 2.5 ppm. How did you get there?

I've tried breach based on the results from Poolcaculator, which showed that I needed to add only 1 to 2 jugs of 96oz 6% breach to bring my FC from 1 to 3. I added 3 jugs in 2 days. The FC didn't really change. Then I had to shock the pool to kill algae. I put in 4 pounds of those powder chlorine products from Leslie's. That brought FC to around 10. I am just thinking to bring FC from 1 to 10, it needs about 7 jugs of 96oz breach based on the calculator, which costs about $11 or $12. 4 pounds of the Leslie's powder chlorine seems to have the same effect, probably more. That costs around $17. Is this cost difference about right? I am trying to have an idea how much it saves on chlorine by using breach instead of Leslie's products. Thanks.
 

svenpup

LifeTime Supporter
Nov 18, 2009
835
Sacramento, CA
ffly said:
Hello! Noooobie here.

Hi TimS, is FC 9.0 too high to swim in? I read only FC below 4 is good to jump in...

Bama Rambler, How do you convert fl ounce to ppm? 182 fl oz = 2.5 ppm. How did you get there?

I've tried breach based on the results from Poolcaculator, which showed that I needed to add only 1 to 2 jugs of 96oz 6% breach to bring my FC from 1 to 3. I added 3 jugs in 2 days. The FC didn't really change. Then I had to shock the pool to kill algae. I put in 4 pounds of those powder chlorine products from Leslie's. That brought FC to around 10. I am just thinking to bring FC from 1 to 10, it needs about 7 jugs of 96oz breach based on the calculator, which costs about $11 or $12. 4 pounds of the Leslie's powder chlorine seems to have the same effect, probably more. That costs around $17. Is this cost difference about right? I am trying to have an idea how much it saves on chlorine by using breach instead of Leslie's products. Thanks.
ffly, first off you should start you own thread with questions so we can keep your info separate from other posters.

It is safe to swim with FC less than shock level, based on you CYA (chart in my sig)

Bama used the pool calculator to determine ppm from fl oz.

Shock is a process, not a product (see my sig). If you got algae you weren't keeping your FC high enough based on your CYA level. if your target was 3 you were assuming CYA = 0 which it almost certainly is not.

The big cost savings come when you take control of your pool and don't let it turn bad. It is always cheaper to maintain than it is to shock.

I recommend that you start a new thread and enter all your information including:
  • FC[/*:m:291zclgg]
  • CC[/*:m:291zclgg]
  • pH[/*:m:291zclgg]
  • TA[/*:m:291zclgg]
  • CH[/*:m:291zclgg]
  • CYA <-- Very Important[/*:m:291zclgg]
How are you testing?
 

TimS

LifeTime Supporter
Sep 21, 2009
214
Central Missouri
ffly,

Is FC 10ppm safe to swim in? As svenpup said, it depends on your CYA (stabilizer, or UV guard, or whatever Leslie's calls it.) Common wisdom around here is that chlorine up to shock level is fine to swim in. At the lowest level on the CYA chart, (CYA 20) shock level is 10ppm, so is safe to swim in. In my pool, I currently have a CYA of 70 which is higher than most around here keep their pools (excluding those with salt water chlorine generators, which are a slightly different beast.) For my CYA level, shock level is 28 instead of 10. I deliberately keep my CYA higher than normal in a (futile) attempt to reduce my chlorine use.

So, in my particular case, yes FC 10ppm is perfectly fine to swim in. The actual available chlorine is much, much lower than 10ppm, since the vast majority of it is bound to the CYA. I don't know exactly how much is really "free" but chem geek could certainly tell you. Is that confusing enough?

The bottom line is "Don't trust the pool store!!!" They usually are staffed by people who don't really understand pool chemistry (not that I really do either :D ) and are just there to sell you stuff.

Last year, was my first with a pool. I had no clue what I was doing (still don't, really :D ) so I just did what the pool store told me to do. Every week was a new set of chemicals to offset what they'd had me do the week before. I was spending well over $100/month in chemicals. I was battling algae without even knowing it. By September, the pool turned green, and I couldn't see the second step anymore. I had to replace my liner anyway, so decided to do it then.

At that point, I found this site, and started reading. Guess where I don't go and who I don't listen to anymore! My pool is cleaner than it was last year, the water is clearer and more sparkly, and I haven't spent a total of $100 since I refilled the pool last year.

Seriously consider getting your own good test kit. Most people here, me included, really like the TF-100 sold by Duraleigh. You can find the link in most any moderator's signature.

Read and re-read Pool School, then read it again. Seriously! There's a lot of great information in there, and it takes a couple of readings to fit it all together.

Once you learn the techniques taught here, you'll be better equipped to manage your pool than the pool store.

Tim.
 

Dejavu2

Member
May 30, 2010
5
North Carolina
I am confused. The Pool company told me to NEVER EVER use bleach in a swimming pool. "It's not the same stuff that pool companies sell." When I asked the lady at the pool company WHY, she replied, "because it has extra stuff in it besides chlorine that you should never put in your pool. (she didn't know what the "extra" stuff was--she said the owner told her that.

What do you experts have to say about that?

I guess I'm just scared to use bleach now.
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
31,502
Sebring, Florida
What do you experts have to say about that?
The post directly above yours says it pretty well.
The bottom line is "Don't trust the pool store!!!" They usually are staffed by people who don't really understand pool chemistry
Thousands of us here on the forum are in big trouble if the pool store lady turns out to be correct. :shock: :shock:
 

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
12,082
San Rafael, CA USA
Just make sure the bleach is UNSCENTED, not a specialty bleach (such as "Outdoor Bleach" or "Splash-less Bleach" which has thickeners) and of reasonable strength, so use Clorox Regular (which should say "6% Sodium hypochlorite" on the bottle) or off-brand Ultra bleach.

The pool store may tell you all kinds of grocery store chemicals aren't the same as from a pool store, but they are wrong. As to whether they are being intentionally deceitful or whether they are just ignorant, you can read the truth about these products in this post.

If the pool store really wants your business, they should start carrying chlorinating liquid at a reasonable price competitive with bleach in your area and should reuse the bottles so that you don't have to recycle them. That's what the pool store in my area does and I use their 12.5% chlorinating liquid in my pool.
 

ffly

Member
Jun 18, 2010
11
sevnpup, TimS,
Thanks for your detailed replies!! I will start a new post with some other questions.
 
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