Testing cheap bleach

[dansdad]

Wife bought bleach from the dollar store, just says sodium hypochlorite on the label but not percentage. What is the proper way to test to see the strength of the sod. hypo. Thanks much.....Dave

[Watermom]

It is probably 3%. Here is a method that one of our members, AnnaK, uses:

Testing the strength of liquid chlorine per AnnaK:
I test the LC I buy every now and then using the following dilutions and test method:

* add 10 ml LC to 1 L water, mix,
* add 10 ml of the mix to 1 L water, mix
* test using the 25 ml procedure multiplying the # of drops by 0.2.

[CarlD]

I take a 10ml eyedropper of the LC, and drop it in 10 liters of water...5 2liter soda bottles...and measure it the way I would measure pool water.

[dansdad]

Ok now I got what to use to test,,,,but are we saying AFTER I make the mixture THEN using my 2006 I test with the powder and go from there?

[CarlD]

The idea is to dilute the LC in a water solution to mimic the pool. So adding 1 gallon of LC to 10,000 gallons in a pool is 1: 10,000.
I mis-wrote above..my eyedropper (glass) is 1 ml, not 10. So....1 ml of LC in 10 liters of water (five soda bottles full) is the same as 1 gallon in 10,000 gallons.

I mix it up in a 5 gallon bucket, then test it with my trusty FAS-DPD test. Whatever it reads is the concentration of the LC/bleach.

However, it's a good idea to test the water FIRST before you add the LC because public water frequently has an FC reading, and you'll want to subtract that.

[dansdad]

Ok Carl never thought about deducting will do.

[dansdad]

ok now I took 1 liter of water and 10 ml bleach and mixed. THEN 10 ml of THAT mix to 1 liter of water, mixed and tested it using 25ml procedure using the 2006. My test which I ran twice came out to .8 Is that bleach that weak? Or should I try 25 ml of the bleach and run the test? I'm kinda at a loss here

[CarlD]

I think you should add 1 ml of bleach to 10 liters of water (less than a 5 gal bucket full) and THEN run your test.

[dansdad]

I will do. I'm doing something wrong. Bleach can't be .8, so I'll do as you say and get back...dave

[CarlD]

Actually, it can be. Liquid chlorine can break down when exposed to light and heat, especially light. But usually high concentration bleach or LC is more vulnerable than low concentration bleach. Just not likely. Still, I've gotten 12% LC that didn't even test at ten, from the now-defunct Branch Brook Pools, and 12% that tests at 14.5 from Sun Pools. The latter consistently tests high...VERY high turnover of their stock.