How to calculate cost per effective chlorine liquid v powder

[rock]

Re: How to calculate cost per effective chlorine liquid v po

- Sodium Dichloro-s-Triazinetrione Dihydrate, typically 99% by wt, available 55%
- Sodium Dichloro-s-Triazinetrione, typically 85% by wt, available 55%

These two are the same.

Oh. I see. I think. Thanks for the clarification. There is dichlor (anhydrous) and there is dichlor (dihydrate).

From now on, I'm never buying a dihydrate that doesn't say on the box the available chlorine because if they don't say it, I will assume it's not good (and that they're trying to hide it).

if you find % Available Chlorine as 55% or so (56%), then you've got nearly pure Dichlor dihydrate which is good.

The only confusing thing left on that topic is how both a 99% & 85% dihydrate can both have 55% available chlorine?
1. Sodium Dichloro-s-Triazinetrione, anhydrous, typicall 99% by wt, available 64%
2a. Sodium Dichloro-s-Triazinetrione Dihydrate, typically 99% by wt, available 55% <== if this has 55% available chlorine ...
2b. Sodium Dichloro-s-Triazinetrione, typically 85% by wt, available 55% <== how can this have 55% available chlorine?

Dichlor dihydrate ... is a Class 1 oxidizer as opposed to the anhydrous Dichlor which is a Class 3 oxidizer

As a related aside, one of the arguments of the Costco 4-in-1 US Patent 5,670,059 is that the shock is not an oxidizer for transportation purposes.

the combination of three components yields a safer composition than for certain of the individual components, such as the chlorine source material. For example, sodium dichloro-s-triazinetrione is classified as an oxidizer per DOT regulations. This classification indicates certain levels of safety risks and transportation constraints. By contrast, clarifier products formulated based on this disclosed invention have been found to be non-oxidizers by DOT test, which carry fewer safety risks and transportation limitations.

 

[JasonLion]

Re: How to calculate cost per effective chlorine liquid v po

The Sodium Dichloro-s-Triazinetrione is stronger, but it has 15% filler, lowering it's total available chlorine so that it is the same as the other (for marketing reasons mostly).

The funny thing about that patent application is that what they "really" mean is that they added some filler, so it isn't as explosive as if it was pure. So what they are really boasting about is that it is less effective.

 

[Pb2Au]

Re: How to calculate cost per effective chlorine liquid v po

Here might be an alternative method of comparing costs. The following are amounts of each chlorine product needed to add 10 ppm of chlorine to 10,000 gallons of water.


Cal Hypo 48% 28.00 oz
Cal Hypo 53% 25.00 oz
Cal Hypo 65% 20.70 oz
Cal Hypo 73% 18.40 oz
Liquid Chlorine 12.5% 102.40 fl oz
Liquid Chlorine 10% 128.00 fl oz
Liquid Bleach 8% 152.70 fl oz
Liquid Bleach 6% 207.40 fl oz
Liquid Bleach 5.25% 239.20 fl oz
Dichlo 56% 24.10 oz
Dichlor 62% 20.70 oz
Trichlor 90% 14.83 oz
Lithium Hypo 28% 47.66 oz
Lithium Hypo 35% 38.13 oz

The trichlor and dichlor would need washing soda to adjust pH.

Just figure your cost for each.

 

[chem geek]

Re: How to calculate cost per effective chlorine liquid v po

The only confusing thing left on that topic is how both a 99% & 85% dihydrate can both have 55% available chlorine?
1. Sodium Dichloro-s-Triazinetrione, anhydrous, typicall 99% by wt, available 64%
2a. Sodium Dichloro-s-Triazinetrione Dihydrate, typically 99% by wt, available 55% <== if this has 55% available chlorine ...
2b. Sodium Dichloro-s-Triazinetrione, typically 85% by wt, available 55% <== how can this have 55% available chlorine?

99% Sodium Dichloro-s-Triazinetrione Dihydrate is IDENTICAL to the combination of 85% Sodium Dichloro-s-Triazinetrione and 14% Water. "Dihydrate" means two water molecules per Dichlor molecule. They don't usually list water as water and just call it any anything else extra that doesn't have to be listed by law (because it is hazardous or is an active ingredient) as "inert ingredients". You get the same physical amount of Dichlor in the two cases, hence the same % Available Chlorine. It's just in the first case (2a) you combine the Dichlor and water together and call it "Dichlor dihydrate" while in the second case (2b) you separately describe the two components.

 

[rock]

Re: How to calculate cost per effective chlorine liquid v po

Here might be an alternative method of comparing costs

I agree. There are multiple methods of comparing costs.
At first I tried using the pool calculator to calculate equivalents; but then someone (Jason?) pointed me to the chem geek's method which has the advantage that the math can be done in the store.

There are three key factors to understand in the chem geek method:
a) liquid calculations are different than solids
b) "full-strength" solids have an easy calculation
c) "diluted" solids reduce that a based on a percentage dilution

99% Sodium Dichloro-s-Triazinetrione Dihydrate is IDENTICAL to the combination of 85% Sodium Dichloro-s-Triazinetrione and 14% Water...You get the same physical amount of Dichlor in the two cases, hence the same % Available Chlorine.

Ah. Thank you for that clarification. It was not intuitive to me how they could have been the same. Now I know. Thanks!

 

[rock]

Re: How to calculate cost per effective chlorine liquid v po

Called 800-859-7946; Pressed 1 for Biolab; Asked for technical support; Got Scott in Technical Solutions; He asked for the 'product code' which is "22112AQU";I asked what's the available chlorine.

He said 36%.
So I'll update the Costco dichlor dihydrate calculations earlier!
Much more (non intuitive) detail here ...

[EDIT 1]: Running the new calculations and comparing the two suggested methods, we get:
a) $55/24 pounds * 100/36 = $6.37/pound of available Cl
b) $55/24 pounds x 100/55 x 85/58.2 = $6.09/pound of available Cl [/EDIT 1]

[EDIT 2]: Since "ChemTura BioLab" owns all three brands under the "Recreational Water Products" umbrella (i.e., AquaChem, PoolTime, and SpaTime), and since the phone number is the same for all three - and since I was told by Customer Support that the only difference was that Lowes and Walmart get the AquaChem stuff while Home Depot asked for a different brand (Pooltime) so as to differentiate themselves from Lowes ... I was suspect of the 56% number for the $119 Pooltime 40 lb. Chlorinating Granules, manufacturer number 22891PTM).

[EDIT 3]:chem geek kindly calculated the correct percentage using this formula in this thread
"the product has 58.2% Sodium dichloro-s-triazinetrione. So compared to Dichlor dihydrate, which is 85% Sodium dichloro-s-triazinetrione (i.e. not including the dihydrate), the product you got was 68.5% of what you would get with a normal Dichlor dihydrate product. ... The % Available Chlorine of 100% pure Dichlor Dihydrate is 55.4% while the typical 99% pure product is 54.9% (i.e. 55%).
0.99*55.4%*0.685 = 37.6% so this is close to the 36% they are quoting on the phone"
[/EDIT]

However, calling the same number that I called for AquaChem, but hitting a different option #1 for "PoolTime", I got "Anita" who said it was 57% for the Home Depot unlabelled dichlor dihydrate. So at least 'that' calculation stands!

In summary, I think we have a decent current survey for one locale plus we have the math for all locals, including liquids, solids, and badly labeled solids. Thanks for all your help.

Good news: I think we came up with good information that does not appear to be in the record on this forum (or anywhere I could find on the net) so, together, we've advanced the science at least a little bit for those who are interested in calculating a more accurate cost for chlorine for comparison purposes.

I'm indebted to ChemGeek and JasonLion for taking the time and energy to help a fellow pool owner!

 

[rock]

Re: How to calculate cost per effective chlorine liquid v po

On the net, there is a poster called "SMS" <[email protected]> who posted this research for phosphate removal cost comparisons:
> Does anyone have a good recommendation for the phosphate remover?

The short answer is Orenda PR-10000. Not available locally, you have to order it but it's the most concentrated and the most cost-effective.
---1-Gallon
---1-Quart

2nd most cost-effective is the Kem-Tek they sell at OSH.
Least cost-effective is the Phos-Free sold at Leslie's.

Here is a [spreadsheet I did on phosphate removers:

Edit: See this thread about lanthanum chloride substitutes:
- Orenda PR-10000 versus cheap Lanthanum Chloride salt crystal

 

[JasonLion]

Re: How to calculate cost per effective chlorine liquid v po

There isn't any need for phosphate remover, cost effective or not. Save yourself the cost and effort of removing phosphates and simply maintain appropriate FC levels and you won't have problems and will save a significant amount of money.

 

[chem geek]

Re: How to calculate cost per effective chlorine liquid v po

When comparing phosphate removers, you need to account for the cost of clarifier that will also be needed unless the product contains that already. I know from experience that Orenda's product does not contain a clarifier and severely clouds the water so a clarifier is needed unless you have a lot of patience and a really good filter. As Jason noted, you should not need to use one if you properly maintain the FC/CYA ratio.

 

[rock]

Re: How to calculate cost per effective chlorine liquid v po

When comparing phosphate removers, you need to account for the cost of clarifier.... you should not need to use [phosphate remover] if you properly maintain the FC/CYA ratio.

Thanks for the reminder & corrective advice on the unnecessary phosphate-removal chemicals.

What you admonish makes sense. I appreciate your patience (which will help others) and will re-read the pool school which clearly says "It is important that you do not allow FC to get too low, or you run the risk of getting algae".

When I refill my pool (currently dry and waiting for a new Jandy valve to arrive), with my very hard well water (>200ppm CH, >100ppm Phospates) I'll try to:
a) Maintain the FAC level (based on the FAC/CYA chart) using liquid chlorine (in the evening)
b) Maintain the CYA as low as I can get away with (no shade, no rain, sun all day) using solid CYA granules dissolved in warm water
c) Maintain the pH on the low side with muriatic acid (my CH & phosphates are high so I think I need to keep pH a bit low)
d) Maintain TA at the optimal levels

For the purposes of this thread, we probably only need to discuss the cost effectiveness of the critical chemicals:
- Sanitizer chemicals (such as chlorine, liquid or solid)
- Acid/Base chemicals (such as muriatic acid & borax)
- Calcium/Alkalinity chemicals (such as calcium chloride & sodium bicarbonate)

After reading the BBB thread, and now that we found the cheapest way to obtain bleach and muriatic acid, I'll have to survey the local supermarkets for the best prices on calcium chloride, borax, and baking soda!

 

[chem geek]

Re: How to calculate cost per effective chlorine liquid v po

b) Maintain the CYA as low as I can get away with (no shade, no rain, sun all day) using solid CYA granules dissolved in warm water
c) Maintain the pH on the low side with muriatic acid (my CH & phosphates are high so I think I need to keep pH a bit low)
:
I'll have to survey the local supermarkets for the best prices on calcium chloride, borax, and baking soda!

With sun all day, you will need a decent amount of CYA in the water, probably at least 50 ppm. Having CYA is not bad -- you just need to maintain an FC level appropriate for it.

Phosphates should have little to do with a required pH level. Your higher CH just means you can keep the TA lower and possibly the pH. With a lower TA, the pH should be more stable anyway by not rising as quickly from carbon dioxide outgassing. Don't try and fight to keep the pH low -- with a lower TA it should settle in to some reasonable level.

I doubt that you'll be needing any borax or baking soda, at least not very often. When using a hypochlorite source of chlorine it's mostly some acid that you need and not much else.

 

[rock]

Re: How to calculate cost per effective chlorine liquid v po

I doubt that you'll be needing any borax or baking soda...When using a hypochlorite source of chlorine it's mostly some acid that you need

UPDATE, exactly 1 year later
That correct statement, by Richard Falk (chem geek), has turned out to be prophetically true, over time.
All my pool normally needs is liquid chlorine, and roughly about a hundred pounds of trichlor tablets over the period of about a year, and a few gallons of muriatic acid as needed to keep the pH around 7.5 or so.

An update on the latest calculations for the current commonly available prices in the Silicon Valley, are:
Normal price liquid chlorine:
Hasa $18.40/4 gallons x 1 gallon/9.7 pounds x 100/10.8 (% by wt) = $4.39/pound FC
Sale price liquid chlorine (using an ongoing web coupon at "The Pool Guys", in Saratoga, CA):
Hasa $21.44/8 gallons x 1 gallon/9.7 pounds x 100/10.8 (% by wt) = $2.56/pound FC; now is $21.62/8gallon x 1gallon/9.7pounds x 1/10.8% by wt available chlorine = $2.58/pound FC

The best-to-worst $cost/pound of 3" trichlor tabs available chlorine in the Silicon Valley appears to be:
Costco was $84.79/40 pounds * 100/84.65 pounds = $2.50/pound FC; now is $80/40 pounds * 100/84.65 pounds = $2.36/pound FC
Leslies was $80/35 pounds * 100/90 pounds = $2.54/pound FC; still is the same calculation.
Home Depot was $75/37.5 pounds * 100/90 pounds = $2.22/pound FC; now is $60/24 pounds * 100/90 pounds = $2.78/pound FC
Lowes was $75/35 pounds * 100/85 pounds = $2.52/pound FC; now is $60/24 pounds * 100/85 pounds = $2.94/pound FC

 

[linen]

Re: How to calculate cost per effective chlorine liquid v po

All my pool normally needs ... and about a hundred pounds of trichlor tablets over the period of a year

Wow, why is that? That would raise your cya by 173 ppm

 

[jblizzle]

Re: How to calculate cost per effective chlorine liquid v po

Lol. That was the thing that struck me as well.

 

[rock]

Re: How to calculate cost per effective chlorine liquid v po

Wow, why is that? That would raise your cya by 173 ppm

I'm a bit confused by your response - because the results seem logical to me - but I do appreciate it as maybe I'm doing something wrong.

To answer why:
At the beginning of pool season last year, I bought a few buckets of the 3" tablets, and they were gone by the end of the year.
That's the hundred pounds. According to the Leslie's pool site, 100 pounds is about 200 tablets.

Where did they go?
I have 3 floaters, two for the main pool, and one for the spa.
Each floater takes about 5 or 6 three-inch tablets - which is about 15 or so tablets at a time.
They last, oh, I don't know ... maybe two weeks? (I don't remember exactly how long because as they shrink, I add one or two or three more at a time).

At 15 tablets every two weeks, I've used up 200 tablets in just 26 weeks, which is about half a year.

BTW, the CYA level is never a problem because of something else which is wholly unrelated.
[ long story ]
Both the self-cleaning pump and the filter pump leak copius amounts of water at a lousy junction that can't possibly be fixed without replacing the pump (as far as I know). The junction that is leaking is exact at the inlet to the pumps, and, there is no place to cut the pipes without replacing about five or six of the Jandy valves. It's sad, but there's PLENTY of room - but the guys who laid out the pipes didn't bother to take advantage of that room - so everything is jammed together fitting to fitting, without a pipe in between. It's all or nothing, so, the leak has been leaking all year. I put in about 500 gallons every two days. Hence, the CYA isn't a problem whatsoever. [ / long story ]

 

[chem geek]

Re: How to calculate cost per effective chlorine liquid v po

So the CYA goes up by 6.5 ppm per week and water dilution reduces CYA by 500*(7/2)/38500 = 4.55% per week. The steady-state CYA in this situation would be 6.5/.0455 = 143 ppm, but if you start out lower you won't get to this amount right away.

 

[rock]

Re: How to calculate cost per effective chlorine liquid v po

Bad news for the price of liquid HASA chlorine in the Silicon Valley.

The one store that had the perennial 2-for-one price of $18.40 + 8.75% tax = for the first 4 gallon HASA cases and then just the $1.61 tax on the second case will discontinued that long-standing promotion at the end of this month!

So, I bought two more cases (at $18.40 + $1.61 + $1.61 = $21.62 for 8 gallons), and will get another two cases to go (at a net of $2.70 a gallon).

 

[rock]

Re: How to calculate cost per effective chlorine liquid v po

...bleach percentages are listed by weight. 6% bleach is 6% by weight, or 5.7% available chlorine. Liquid chlorine is listed by trade percentage. 12.5% trade chlorine is 11.6% available chlorine. In both cases the actual strength varies with age, higher than the listed strength when it is freshly manufactured, lower than the listed percentage if it has been sitting on the shelf for a long time.

It has been another year, so I was doing another very detailed survey of chlorine prices in the Silicon Valley, when I re-read this thread, and that statement above seems contrary in one respect to the edited equation in the OP:

a) liquid chlorine:
$cost/gallon x 1gallon/9.7pounds x 100/10.8 (% by wt) = pounds available chlorine

b) liquid bleach:
$cost/gallon x 1gallon/9.0pounds x 100/5.7 (% by wt) = pounds available chlorine

c) solids:
$cost/pound x 1/??% by wt available chlorine, as listed on the container

Is the correct HASA liquid chlorine equation multiplier "1/10.8% by wt" or "1/11.6% by wt"?

 

[JasonLion]

You always want to use the weight percentage in that particular equation. For liquid chlorine weight % is roughly trade percentage / 1.05.

 

[chem geek]

The above is not quite right.

12.25% Trade which is % Available Chlorine by volume is 10.78% Available Chlorine (by weight) assuming 1.16 g/ml density and is 11.31% sodium hypochlorite by weight.

Weight % Available Chlorine = Trade % / Specific Gravity = (Weight % NaOCl) * Cl2_g_mole / NaOCl_g_mole = (Weight % NaOCl) * 0.9525
So Weight % NaOCl = 1.05 * Weight % Available Chlorine

The divisor in those equations calculating pounds of available chlorine are "% Available Chlorine (by weight)".

While chlorinating liquid is usually sold by Trade %, the percentage for regular bleach is usually weight % of product (i.e. sodium hypochlorite) so 8.25% bleach (weight % of sodium hypochlorite) is 7.86% Available Chlorine (by weight) and assuming a 1.10 g/ml density this is 9.08% Trade (% Available Chlorine by volume).