Chlorine Pricing and Questions

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Ale_Brewer

Ale_Brewer

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Aug 7, 2015
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Plano, TX
Moderator Note - Moved from this thread : Breakdown of bleach over time by storage temperature - Page 2


chem geek said:
I had the Trade % wrong for the 8.25% bleach. I've corrected that in my post. It's 8.64%.
Click to expand...

So is trade % = % by volume as opposed to % by weight (what's listed on the bottle)? I'm looking at a bottle of bleach that says "Sodium Hypochlorite....8.25%" and "Yields 7.86% Available Chlorine". What am I looking at here with this bleach?

***EDIT*** I put together a formula to figure price per ounce of chlorine so I can compare cost of store-bought to HASA(12.5%). Just need to know which number to plug into the formula.
 
Re: Breakdown of bleach over time by storage temperature

Yes, Trade % is % Available Chlorine by volume. The 7.86% Available Chlorine you see on the bleach bottle is % Available Chlorine by weight. The 8.25% is the weight % of sodium hypochlorite. Available Chlorine is in molecular chlorine (Cl2) units. 8.25 * (70.906 g/mole Cl2 / 74.442 g/mole NaOCl) = 7.86. The Trade % for this bleach depends on its density (specific gravity) which is around 1.10 g/ml so Trade % = 7.86 * 1.10 = 8.65%. If you were to add one gallon of this bleach to 10,000 gallons of water, it would increase FC by 8.65 ppm.

As for what to use for price per ounce, it doesn't matter so long as you are consistent for all products. I think that the Trade % is the most useful since it relates directly to the volume of product you would add and usually the price of the product is per volume (i.e. gallon) and not per weight. So Trade % is better to use when figuring the price of chlorine per fluid ounce.
 
Re: Breakdown of bleach over time by storage temperature

Did we just slip and fall into the deep end? chem geek you are my new hero. So the 12.5% stuff I'm getting from HASA...is that 12.5% NaClO by weight or 12.5% available chlorine by volume (trade %)?


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Re: Breakdown of bleach over time by storage temperature

Chlorinating liquid is normally quoted as Trade %, but I've seen bottles of it where they say it's 12.5% sodium hypochlorite. The actual values change more rapidly but I'd just assume it's 12.5% Trade. I get Hasa from my pool store and when I add it to the pool the FC responds as if the 12.5% is Trade % though sometimes it's higher at first and of course over time it drops as it degrades.

Assuming the Hasa is 12.5% Trade, then that is 12.5/1.16 = 10.78% Available Chlorine (by weight) and is 10.78 * 74.442 / 70.906 = 11.31% sodium hypochlorite (by weight).

PoolMath assumes anything 10% or higher is in Trade % while below 10% it's in weight % sodium hypochlorite. That was a change we made some months ago to be a little more accurate (some people actually noticed the difference in their pools and were complaining about not matching PoolMath).
 
Re: Breakdown of bleach over time by storage temperature

Yes, that is correct. If you set PoolMath to 10,000 gallons and go from 0 to 8.65 ppm FC it says 128 fluid ounces of 8.25 weight % bleach while if you say to go from 0 to 12.5 ppm it says 128 fluid ounces of 12.5 trade % chlorinating liquid. I was wrong about the cutoff, though. It looks like 9% and below is weight % while anything above 9% is Trade %.

Likewise, in the "Effects of adding chemicals" section, adding 128 fluid ounces of "6% bleach" gives 8.5 ppm FC while "12.5% bleach" gives 12 ppm FC. Unfortunately there aren't a lot of decimal places so if you add 12800 fluid ounces for "6% bleach" you see 849 which isn't quite correct while for "12.5% bleach" you see 1250 which is correct. "6% bleach" gives the correct 617 (though 5.25% is wrong giving 540 instead of 535) so I'm not sure why the 8.25% is off in this section. The code looks like the following:

Code: 
	case 0:					// 5.25% bleach
		oz=oz*525/600;
	case 1:					// 6% bleach
		oz=oz*600/825;
	case 2:
		oz=oz*0.84867552;
	case 3:					// 10% bleach
		oz=oz*100/125;
	case 4:					// 12.5% bleach
		result="raise FC by "+Format(oz / GetGallons() * 976.562);
		result=result+" and raise Salt by "+Format(oz / GetGallons() *
			1607);
		break;

and I believe it should be the following

Code: 
	case 0:					// 5.25% bleach
		oz=oz*525/600;
	case 1:					// 6% bleach
		oz=oz*600/825;
	case 2:					// 8.25% bleach
		oz=oz*(825*1.10*70.906/74.442)/1000
	case 3:					// 10% chlorinating liquid
		oz=oz*100/125;
	case 4:					// 12.5% chlorinating liquid
		result="raise FC by "+Format(oz / GetGallons() * 976.562);
		result=result+" and raise Salt by "+Format(oz / GetGallons() *
			1607);
		break;

and also for consistency the text options (elsewhere in the code) should say "10% chlorinating liquid" and "12.5% chlorinating liquid" to distinguish these from bleach in terms of being Trade (volume) % Cl2 instead of Weight % NaOCl.
 
Re: Breakdown of bleach over time by storage temperature

Does this math look right? I did a quick calculation on my phone's calculator before doing this to compare pool store to wal-mart and it was within 1 cent of each other and now this shows a big price difference. I quit drinking coffee so I'm a little slow in the mornings :-?

price per gallonprice w/ taxtrade %ouncesfactoroz of NaClO$ per oz.$ per oz of NaClO
pool store$5.00$5.4112.501280.125016.00$0.0423$0.6762
wal-mart$2.94$3.188.251210.08259.98$0.0263$0.2626
lowe's$3.78$4.0910.001280.100012.80$0.0320$0.4092
 
Re: Breakdown of bleach over time by storage temperature

Ale_Brewer said:
Does this math look right? I did a quick calculation on my phone's calculator before doing this to compare pool store to wal-mart and it was within 1 cent of each other and now this shows a big price difference. I quit drinking coffee so I'm a little slow in the mornings :-?

price per gallonprice w/ taxtrade %ouncesfactoroz of NaClO$ per oz.$ per oz of NaClO
pool store$5.00$5.4112.501280.125016.00$0.0423$0.6762
wal-mart$2.94$3.188.251210.08259.98$0.0263$0.2626
lowe's$3.78$4.0910.001280.100012.80$0.0320$0.4092
Click to expand...

Well, first all are not Trade %. Bleach is Weight % not volume %

There are automated calculators out there that members have created, like this one Chlorine Price Per Ounce Calculator
 
Re: Breakdown of bleach over time by storage temperature

That is true. Forgot to convert to trade %. Something is still off. Here's the updated trade % corrections with the prices from the calculator you gave me on the far right. Those are the figures I got initially so I have a formula wrong somewhere.

price per gallonprice w/ taxtrade %ouncesfactoroz of NaClO$ per oz.$ per oz of NaClOcalc
pool store$5.00$5.4112.501280.125016.00$0.0423$0.6762$0.34
wal-mart$2.94$3.188.651210.086510.47$0.0263$0.2753$0.32
lowe's$3.78$4.0910.481280.104813.41$0.0320$0.4288$0.32


*** NM, I found my error! ***
 
Last edited:

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Re: Breakdown of bleach over time by storage temperature

Well, here is the way I look at it. I would never buy chlorinating liquid from Lowes/Home Depot due to the manner in which it is stored in their locations (generally in the outdoor garden area) so that takes them off the list.

I factor my time into the equation....You probably have more pool stores available so you pass them often. I have to go out of my way for them, so again they are off the list.

I have found my local Dollar General carries generic 8.25% with very recent date codes less expensive than WalMart by a few cents a bottle. I drive by it daily, the store is small so it's quick in/out and there is seldom a line. If I'm at WalMart for something I'll pick it up there. if not Dollar General is quick, easy and just as inexpensive as other places
 
Re: Breakdown of bleach over time by storage temperature

Tim, you make some very good points. Time is a big factor for me as well. I'm currently using 12.5% HASA from my local pool store and I'm happy with it. I was just wondering if I could save some money in the long run. I avoid wal-mart like the plague but there is a dollar store really close so I might check them out.


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Re: Breakdown of bleach over time by storage temperature

Do not buy the 96 oz from Dollar tree. It is only 1-2% They do sell a 128 oz version that I have tested as high as 5+% but others have not had the same experience. The datecode is on the case. I only buy it by the case. There is a thread called 'bleach prices 2015' where I show a pic of the label on the case.

Tim was talking about Dollar General.

- - - Updated - - -

Here is the link: Bleach Prices 2015 - Page 19
 
Re: Breakdown of bleach over time by storage temperature

As a rule 8.25% will be marked with the concentration.

Unmarked bottles are below that, anywhere down to 1%. Stay away.
 

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