Tds And When To Dump The Water?

[quantumchromodynamics]

OK, in my initial analysis, I did get the correct numbers.

My alternative analysis assumed that the bleach has a mass of exactly 1,100 grams per liter due to the given specific gravity of 1.1 of the bleach. However, the numbers don't work with that mass per liter.

If I assume that the correct mass is 1,119.95 grams per liter, then the numbers work out correctly.

There will be 67.197 grams of NaOCl and 52.754 grams of NaCl.

That will add a total of 105.508 ppm of TDS.

The amount of chlorine added will be 64.0051 ppm.

Therefore, 10 ppm of chlorine will add 16.48 ppm of salt.

1 ounce of 6 % bleach added to 100 gallons of water will add 8.243 ppm of salt.

1 ounce of 6 % bleach added to 100 gallons of water will add 5.0004 ppm of chlorine.

128/5 X 8.243 = 211 ppm salt added.

My mistake in my alternative analysis was to use the wrong density for the bleach. It seems that the correct value is 1119.95 grams per liter and that the given specific gravity is rounded off to 1.1.

[chem geek]

Just making sure, but do you understand that the TDS increase is also 16.5 ppm (or slightly higher) because the oxygen in the hypochlorite goes away when the chlorine gets consumed/used? So the TDS that is net added after accounting for chlorine usage/consumption IS salt and essentially the same as that salt amount.

[quantumchromodynamics]

Just making sure, but do you understand that the TDS increase is also 16.5 ppm (or slightly higher) because the oxygen in the hypochlorite goes away when the chlorine gets consumed/used? So the TDS that is net added after accounting for chlorine usage/consumption IS salt and essentially the same as that salt amount.

Yes, got it, thanks for the help.

Clorox should specify the specific gravity of the bleach as 1.11995 to avoid confusion.

[OttawaGreg]

Just making sure, but do you understand that the TDS increase is also 16.5 ppm (or slightly higher) because the oxygen in the hypochlorite goes away when the chlorine gets consumed/used? So the TDS that is net added after accounting for chlorine usage/consumption IS salt and essentially the same as that salt amount.

OK, it's official.. the geeks have hijacked the thread ;-) time for a dip...

[simonc]

OK, it's official.. the geeks have hijacked the thread ;-) time for a dip...

QCD & Chem Geek -

You can say that again. Specific gravity? Moles? Sodium this and sodium that?

So ... back to my original question ...

Approximately how many ppms of salt does a 500 gallon tub have after using up a gallon of 6% bleach?

The BEST answer would be a SINGLE number WITHOUT a "it depends" in the answer. Positive integers (not too big!) are things I can comprehend.

Thanks to both of you for doing the analysis and calculations, but all I really wanted was a number.

- Simon

[chem geek]

The answer is a little over 200 ppm salt (204 ppm or somewhat more). This amount of bleach in 500 gallons is around 123 ppm FC.

Note that a jug of 6% bleach is actually 3/4 gallon (unless you get the 1-1/2 gallon larger size) so that would be a little over 150 ppm salt (153 ppm or somewhat more). This amount of bleach in 500 gallons for this jug is around 93 ppm FC.

[quantumchromodynamics]

You can also use the poolcalculator to see the effect of adding chemicals by using the "Effects of adding chemicals" section, which shows that adding 128 ounces of 6 % bleach to 500 gallons will add 203 ppm of salt.

[cofive]

Just making sure, but do you understand that the TDS increase is also 16.5 ppm (or slightly higher) because the oxygen in the hypochlorite goes away when the chlorine gets consumed/used? So the TDS that is net added after accounting for chlorine usage/consumption IS salt and essentially the same as that salt amount.

OK, it's official.. the geeks have hijacked the thread ;-) time for a dip...

It is like watching the "The Big Bang Theory" show...LOL But, thanks again guys, you do provide a wealth of information that does eventually come together for the average user. I'm a convert to the dichlor-bleach method. I use only a couple chems (baking soda, muriatic acid, calcium chloride); test twice a week with drop tests; and am a happy tubber. Oh yeah, and I don't worry about TDS with this system.

Ken

[simonc]

You can also use the poolcalculator to see the effect of adding chemicals by using the "Effects of adding chemicals" section, which shows that adding 128 ounces of 6 % bleach to 500 gallons will add 203 ppm of salt.

QCD -

Thanks. Until you pointed out the "Effects of adding Chemicals" section in the poolcalculator, I never even noticed it existed! It's at the bottom of the page ... I never looked down that far.

I sincerely appreciate your efforts to not only provide information but also to "educate" the rest of us. Actually, I find the chemistry interesting, although somewhat incomprehensible.

Without technical people like yourself, this forum would be much less useful.

Thanks,

- Simon

[tagyerit]

yes they have BLESS THEM.

Just making sure, but do you understand that the TDS increase is also 16.5 ppm (or slightly higher) because the oxygen in the hypochlorite goes away when the chlorine gets consumed/used? So the TDS that is net added after accounting for chlorine usage/consumption IS salt and essentially the same as that salt amount.

OK, it's official.. the geeks have hijacked the thread ;-) time for a dip...