How to test bottled bleach?

[hamop78]

I test every batch of bleach I buy ---- Using 1000 ml (1 Liter) of UNCHLORINATED water (from a well or distilled), place .1 ml of the sample from your bleach bottle -- mix and test.

As for the dilution method for testing bleach I use a 1000 ml volumetric flask and a medical syringe used to perform the standard tuberculin “Tine” test. The syringe has a total capacity of 1 ml but is graduated in .01ml graduation intervals with major graduations at .1ml. The dilution method is accurate within .1 ml @20 deg C.
Testing is done using the FAS-DPD method, using a 25ml sample size, again yielding accuracy within .2 ppm in a 10000 to 1 dilution.

I have found the results to be repeatable with a 95% confidence level (in scientific terms [95 out of 100 tests]).

The results of the test is equal to the percentage of bleach.

[ChuckD]

Now there's a sticky.
Thanks, very useful!

[CarlD]

I test every batch of bleach I buy ---- Using 1000 ml (1 Liter) of UNCHLORINATED water (from a well or distilled), place .1 ml of the sample from your bleach bottle -- mix and test.

As for the dilution method for testing bleach I use a 1000 ml volumetric flask and a medical syringe used to perform the standard tuberculin “Tine” test. The syringe has a total capacity of 1 ml but is graduated in .01ml graduation intervals with major graduations at .1ml. The dilution method is accurate within .1 ml @20 deg C.
Testing is done using the FAS-DPD method, using a 25ml sample size, again yielding accuracy within .2 ppm in a 10000 to 1 dilution.

I have found the results to be repeatable with a 95% confidence level (in scientific terms [95 out of 100 tests]).

The results of the test is equal to the percentage of bleach.

Hey, anybody can do it with THOSE tools!

(just kidding! )

The reason I used the 1.8ml and 5 gallon bucket is that Ben's PS-232 kit has a measure that really close to what you need--and EVERYONE can get a 5 gallon bucket.

Another idea: Lots of infants' medicines have eyedroppers marked off in ML, some with exactly 1.0 ML. Take one from a used-up or expired bottle, and mix it with 10 liters of water. (wash it first! )

10 liters???? What's that???? Why, that's five 2-liter soda bottles! --in that good old reliable 5 gallon bucket. You probably have at least one 2-liter bottle in your recycling right now.

What you lose in precise measuring that hamop78 does will be gained by using ten times as much water and bleach, so your results should be as accurate as his. But you don't look as cool!

[cleancloths]

Not sure I understand why the need to test bleach? So what if it is not exactly 5.25% or 6%, you will know what you've got once you test your pool. I think there is more variability in the chlorine demand of the pool than there is of the bleach.

[KurtV]

cleancloths,
Bingo.

[aylad]

Not sure I understand why the need to test bleach? .

The original problem was that the concentration wasn't listed on the bottle....and there's a huge difference between 3% bleach and 6% bleach when it comes to amounts needed and lugging that many bleach jugs around!

Janet

[CarlD]

Also, when you buy "12.5%" liquid chlorine at the pool store, it may be as high as 14.5% or it may have been sitting around. In which case, it could now be only 10%, or even only 6%.

Or YOU could have had LC sitting around and you want to know how strong it still was.

So you might be adding "12.5%" and measuring accordingly and only getting half the bang for the buck.

I dunno...it makes sense to me as an occasional test. I first came up with these formulae because I had to test my own LC in the big blue carboy and wanted to know just what I had.

[ChuckD]

Here's another:
I bought several 5 gal. carboys of 12.5& last summer and I've still got one unopened that's been in an unheated garage. I'll be testing it to see how it stands now.

[KurtV]

Here's another:
I bought several 5 gal. carboys of 12.5& last summer and I've still got one unopened that's been in an unheated garage. I'll be testing it to see how it stands now.

That's what I don't get. Why test it? Wouldn't it be much easier to dump a gallon (or half gallon or whatever makes sense in your pool size) in the pool, wait 15 minutes, and then test your pool water (as you probably do once a day or so anyway), and see how the addition affected your pool water? You can very easily estimate what percentage of chlorine the bleach was using bleachcalc from that. Certainly to an accuracy that's more than adequate for our purposes.

Is testing your bleach an interesting exercise? Sure. Is it necessary? Nope. Is it even helpful? Not very. And it is more hassle than the alternative.

[CarlD]

That's what I don't get. Why test it? Wouldn't it be much easier to dump a gallon (or half gallon or whatever makes sense in your pool size) in the pool, wait 15 minutes, and then test your pool water (as you probably do once a day or so anyway), and see how the addition affected your pool water? You can very easily estimate what percentage of chlorine the bleach was using bleachcalc from that. Certainly to an accuracy that's more than adequate for our purposes.

Is testing your bleach an interesting exercise? Sure. Is it necessary? Nope. Is it even helpful? Not very. And it is more hassle than the alternative.

Then don't do it. Seriously. Everybody has their own way of doing things. If this doesn't suit you, don't do it.

Me, I prefer to know what I'm dumping into my pool before I dump it in. I prefer to know how much I need to get the effect I want. But that's me and that's my pool.

If it doesn't suit you or your pool care system,
then just don't do it.