Bleach and Pucks?

nitz369

Well-known member
Mar 22, 2008
83
#1
I am not sure if this is crazy or not but does anybody use bleach daily and trichlor pucks as well?

My issue is I am going through a ton of bleach, about 100oz daily for my 12,000 gallon pool. my CYA is 40-50 so I bring chlorine up to 8ppm at night everyday. I am losing 4ppm daily.

Could I offset some of the bleach use by using trichlor pucks? How much chlorine do those add anyhow? Would this dfeat the purpose of using bleach since it adds CYA?

I have done the TF-100 CYA test multiple times and everytime I am confused, do I go until I can't see the dot at all? I mean i get to a point where it is **** hard to see it but can still see it just barely, is that right?
 

JasonLion

TFP Expert
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May 7, 2007
37,879
Silver Spring, MD
#2
Trichlor adds chlorine, CYA, and lowers PH. You probably don't want to use trichlor for very long because your CYA level is already good and CYA is difficult to lower.

Losing 50% of your FC over a sunny day is normal for a CYA level around 50.

You keep going till the black dot completely vanishes and all you see is a uniform white cloudiness.
 

JasonLion

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#4
If you have lots and lots of direct sunlight you could try CYA levels in the 60 to 80 range. That requires higher FC levels, but protects the chlorine from sunlight much more effectively, so the total chlorine usage goes down.
 

nitz369

Well-known member
Mar 22, 2008
83
#5
Just did a test that I have been forgetting about.

my FC was 3.5 and I added 112oz 6% chlorine per the pool calculator, it is now and hour later and tested again FC is 6.0, but the amount of chlorine added should have brought to 8.

what is wrong? maybe i'm not using 4ppm per day
 

nitz369

Well-known member
Mar 22, 2008
83
#6
forgot to add that CC is 0 or extremely close to 0. I just shocked a week ago as well, no visible algae or anything poollooks perfect.
 

smuggs

LifeTime Supporter
Sep 10, 2007
141
Gloucester County, NJ
#7
I was just thinking about this same issue this morning. I was away for the last couple days and had my wife checking the CL levels. We have had VERY sunny days for the last week and I can't seem to keep a FC level above 2. My CYA level is about 40 and I am using a LQ with 12.5% chlorine. I was thinking that since my CYA level is reasonable, I could supplement with pucks at a low flow rate. Thoughts?
 

JasonLion

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#8
If you want your CYA level to go up, and you keep an eye on PH so it doesn't go too low, trichlor tablets/pucks are a reasonable and convenient choice. But it is very easy for trichlor to get overused and then CYA levels get too high and then there can be problems.

There are many ways chlorine levels can come out differently than you expect. 6% bleach isn't always 6%. Some people have bought 6% bleach that was actually as high as 8% or as low as 0%. Bleach spoils slowly in storage so they usually manufacture it at a slightly higher percentage and then it goes down depending on how long it has been on the shelf and how hot it gets. It takes many months for there to be significant loss of strength at reasonable temperatures, so it isn't usually an issue, but sometimes it is.

It is also possible for there to be various errors in your measurements, pool size might be different, FC level might be a little higher or lower than the test result, etc. None of the tests/measurements are ever exact.

And, of course, it is possible for the pool to have higher chlorine demand than you expect. There could be something in your water consuming chlorine.

When the results aren't what you expect, it is often difficult to sort out which of these effects is at work in your situation.
 

smuggs

LifeTime Supporter
Sep 10, 2007
141
Gloucester County, NJ
#9
Jason -

yep...exactly why i'm asking...I don't quite understand why I appear to be using so much FC. My CC's have consistently been ZERO since opening the pool in April. With the high temperatures we have been having, the kids have been in the pool pretty constantly. My PH seems to float upward since stopping the use of the trichlor pucks about a month ago, and since there's been a lot of splash out combined with evaopration, i'm replacing water pretty consistently (1-2 inches a week), my CYA level has trended downward. So, you would think using an active combination of bleach and pucks is OK, so long as I'm monitoring the chemistry?
 

frustratedpoolmom

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In The Industry
May 20, 2007
12,177
SWSuburban Chicago, IL
#10
Do you have some left over?

I feel like they are not usually recommended because of their cost and the assorted problems that develop from continous use by people who don't understand the resulting chemistry problems.

You do seem to "get it", so if you already have them and/or don't mind the added expense, sure you can use them. Just keep testing and making the appropriate adjustments to your water chemistry.

I did go thru a period of ajustment after I stopped using tri-chlor. I LOVED the convenience and it took time for me to "get over them"... :wink:
 

JasonLion

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May 7, 2007
37,879
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#11
You can rule out something in the water using up chlorine by doing an overnight FC loss check. If FC remains the same overnight, or only drops by 0.5, then your water is fine.
 

Rangeball

Well-known member
May 25, 2007
785
#12
Depending on your area, this spring there's been a TON of pollen in the air, much more than previous years.

If you are losing FC overnight, this could be a likely cause.
 

smuggs

LifeTime Supporter
Sep 10, 2007
141
Gloucester County, NJ
#13
the overnight FC loss is a good idea....didn't think of that (though I should have....no different that what you want to do if shocking). Since I'm around this weekend, I'll give it a shot. I also just adjusted my pump schedule to go 2.5 hours in the AM and then 9.5 hours in the PM (until 10PM) thinking that some more time running in the evening hours would help the FC situation since we pretty much get full sun from 10am onward.

as for the pucks...I do have some leftover ones. The only problem is that I would need to drill another hole in my plumbing if I want to run both the LQ and the rainbow puck chlorinator (i used the existing hole for my LQ)....besides that, i think i'll do it just to give me some flexibility.
 

Exchemist

Well-known member
Oct 5, 2007
86
Philadelphia, PA
#14
I'm seeing exactly the same thing as nitz369. My CYA is about 60 ppm. The water temperature is between 84 and 87 F which is the highest I've ever seen it.

I boost up the chlorine to 8 ppm each evening and by the next evening it's between 0 and 3 ppm. CC is always under 0.5 ppm and the water is generally clear. Given the heat, sun, and bather load this chlorine consumption seemed reasonable to me.

I'm buying 6% bleach from Costo at $7 for three 182 oz bottles. So, the 64 oz I typically add each evening costs $0.82.
 

Rockcrawler

Well-known member
May 9, 2007
174
El Paso, Texas
#15
I live in El Paso, where we get 300 day a year of sun, I cover the pool with a solar cover anytime anyone isn't swimming, the solar cover/or any cover will prevent the sun from eating up your clorine, I know its a pain in the *** I've been doing it for 3 yrs now, but it save on chemicals or wear and tear on your SWG

Rob
 

nitz369

Well-known member
Mar 22, 2008
83
#16
Okay so did another CYA test and it is 35 actually, it was 50 earlier, the autofill must be adding lots of water lately.

Soooo.....

Could my issue be too low of CYA?? Should I bump it up to 50?