How can I test bleach for myself to confirm the concentration of Sodium Hypochlorite?

[dclynds]

In the absence of my standard go-to 6% bleach at aldi, I went to Pinch A Penny Pool Supply and got a 2.5 gallon jug of supposedly 10.5% Sodium Hypochlorite. I am skeptical of that 10.5% concentration. Yesterday, my FC was 4.0 pp. , so I added 40 oz yesterday which should have bumped FC up by 2 ppm. However, when I tested again today, the FC was 3.5 ppm. Very surprising! Besides monitoring effect of pool water over time, what is a quicker and more direct method to test a sample of bleach directly to determine its true Sodium Hypochlorite concentration?

Thanks,
Daniel

 

[mknauss]

10 ml of bleach in 1 liter of water is 10 ppm. Use distilled water.

 

[tillmac62]

Yes. Take 0.1ml of your "bleach" and dilute to 1 liter. Test this sample as you would your pool/spa sample (10 ml using the FAS-DPD) method. The result, in this case, is pph (%) rather than ppm. For example, a 6% bleach concentration will yield 6 as the test result.

 

[dclynds]

Yes. Take 0.1ml of your "bleach" and dilute to 1 liter. Test this sample as you would your pool/spa sample (10 ml using the FAS-DPD) method. The result, in this case, is pph (%) rather than ppm. For example, a 6% bleach concentration will yield 6 as the test result.

Take 0.1 mL and dilute to 1 liter? 0.1 mL seems like an awfully small volume so just double checking. Thanks for the help

 

[mknauss]

ppm to ml/l Converter, Chart -- EndMemo

Concentration percentage unit conversion between part per million and milliliter/liter, milliliter/liter to part per million conversion in batch, ppm ml/l conversion chart

www.endmemo.com

I messed up in my post above. It is 0.1 ml of 10% to 1 liter of water for 10 ppm.

You are better off adding to your pool and determining the approximate % that way.

 

[taylortechnologies]

Hi Daniel,

We offer a chlorine bleach test kit (K-1579) 1 drop = 10 or 100 ppm; 1 drop = 0.05 or 0.5%. Sounds like this may be what you're looking for.

Drop Test, Chlorine (Bleach), Iodometric, 1 drop = 10 or 100 ppm; 1 drop = 0.05 or 0.5%

More info: https://www.taylortechnologies.com/en/Image/GetDocument/589

 

[YippeeSkippy]

Wow.... I think for $109 I'd skip the test, pour it into my pool and see how it did.

Maddie

 

[griffths]

I just looked into this and you can purchase the reagents for about 70.00 and store in your own box. Still not sure if I am willing to bite, however I do purchase in bulk and usually end up with multiple cases in the basement over the winter that I am curious about.

Empirically, the bleach does seem to be equally as effective in the spring as the previous fall but it would be nice (in an OCD way) to know exactly how much it has degraded over the 6-7 months it has been sitting in the basement.

 

[Oly]

As mentioned above use pool math to estimate the result of your adding a known quantity of the chlorine liquid you have available. Test your pool water for FC before and after an hour of the application. Confirm the FC result and if different from your earlier estimate, alter the % bleach in pool math to find your answer. OCD relief with the test kit you already own.