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fission7x
09-17-2006, 09:10 AM
I must be doing something wrong. I've been thinking that the BBB method was less expensive than using pool-specific chemicals, but the math doesn't add up.
I read on this fourm somewhere that 1 pound of pool-specific granular chlorine is equal to 2 gallons of 6% bleach.
From various places on the web, 50 pounds of stabilized granulated chlorine runs about $155. The liquid bleach I have been using is 5.25% bleach and costs $1.70 per gallon. With reference to 50 pounds of granulated chlorine, the equivalent amount of 5.25% liqud bleach would be 114.29 gallons. This much bleach would cost approximately $194.29.
This doesn't seem economical to me.
Are my comparisons all screwed up?

Of course, this is neglecting any effect pool-specific chlorine has on CYA levels.

RavenNS
09-17-2006, 09:26 AM
I agree with you, it just all depends on what things cost in your location at the time.
Sometimes bleach here in NS is not at all a good deal ( a couple dollars per bottle), & sometimes it's on a great sale like 0.88 cents a bottle...

same with Borax. I find it difficult to find, most stores don't seem to carry it anymore (here). And the price can be much more expensive then buying Ph Up at a pool store. Factor in being able to buy PH up at large dept stores, & it is actually a lot cheeper ( here) to buy regular PH up.

Buying a 50 lbs bag of food grade baking soda though is a huge savings over pool store though :D

duraleigh
09-17-2006, 11:06 AM
Being cheaper can be a reason for BBB, but certainly not all or even the primary reason, IMHO.

1. Simplicity

2. Understanding you don't need "magic" ingredients

3. Understanding that many pool store products have unwanted side affects

4. The convenience of grocery store purchases instead of going to the pool store

All these are probably better reasons.

Mom2Czars
09-17-2006, 11:49 AM
I was able to get the 6% bleach from Walmart for $2.29 per 1.42 gallon bottle all summer ($1.60 per gallon). Does the granular chlorine have CYA in it? That would be my only concern about it. If it doesn't, I might seek some out myself, since I'm looking for a good method of getting chlorine under the stairs in my ABG pool. If you're using stabilized chlorine, you'll be having to pay more attention to your pH.

Because my pool is just 13.5k gallons, once my water is balanced I only need about 3 cups of bleach per day to keep it at a good level. Because I don't use the pucks and my liner is vinyl my pH stayed put all summer too. So it cost me about 1 large bottle of bleach per week to run my pool. I did have to add a bit more from time to time related to weather and bather load, but not too often. Seems pretty cheap to me, especially compared to some other methods.

ivyleager
09-17-2006, 01:21 PM
My personal experience is that the bleach method is much more expensive and time consuming when one is dealing with a large volume pool, such as yours. I'm looking at SWC's for next season.

CaryB

chem geek
09-17-2006, 01:39 PM
I read on this fourm somewhere that 1 pound of pool-specific granular chlorine is equal to 2 gallons of 6% bleach.
The following table gives the equivalent values for one pound of each form of chlorine and also shows the affect in a 10,000 gallon pool (with 100 ppm TA, 30 ppm CYA and 7.5 pH initially) where the pH and TA are shown AFTER the chlorine is used up (by disinfection, oxidation, breakdown from sunlight).


1 pound of...
Form of Chlorine Equiv. 6% Bleach FC CYA CH pH TA
1 pound 6% Bleach 0.11 gallons +0.7 0 0 0 0
1 gallon 6% Bleach 1.0 gallon +6.2 0 0 0 0
Tri-Chlor 1.8 gallons +11.0 +6.7 0 -0.41 -7.7
Di-Chlor 1.1 gallons +6.6 +6.0 0 -0.21 -2.3
Cal-Hypo 1.3 gallons +7.7 0 +5.5 +0.77 +11.3
Chlorine Gas 1.9 gallons +12.0 0 0 -0.62 -16.9

If the chlorine you are referring to is "granular", it is more likely to be Di-Chlor as Tri-Chlor is typically in the form of solid pucks or tablets (3" or 1" in diameter). The ingredient label should say something that makes it obvious (like "...dichloro..." or "...trichloro...").

Prices vary across the country, but it may be that chlorinating liquid from your pool store or a hardware store might be more economical for you. I am able to get 12.5% chlorinating liquid for $2.50/gallon so the price of 6% bleach would need to be less than about $1.25/gallon to be equivalent. So you may find that you can find a better deal for chlolrinating liquid than bleach in your area (and you'll carry less weight for the same amount of chlorine).

As for using a lot of chlorine because of the size of your pool, that is very true though having a pool cover will help cut down consumption considerably. Because of my electric pool cover, I only use about 0.5 ppm or less of chlorine per day so that's about 1 cup of 12.5% chlorinating liquid per day in my 16,000 gallon pool. Of course an SWCG system is the easiest method of generating chlorine of all (and like liquid chlorine, has no CYA nor CH increase and is fairly neutral in pH though most users see a pH rise possibly due to carbon dioxide outgassing from the aerating hydrogen bubbles that are produced by the SWCG). Another way to reduce chlorine consumption is to add Borax to your pool to get to 50 ppm Boron content (see this thread (http://www.poolforum.com/pf2/showthread.php?t=4712) for more info on how Borax reduced chlorine consumption by acting as an algicide so that chlorine didn't have to).

Richard

CarlD
09-17-2006, 09:24 PM
I find having to drain half my water and refilling to lower CYA from too many pucks to be VERY un-economical.

Then you have to toss in the cost of all those boxes of Borax you need because the pucks make your pool too acid.

Then you have to buy tons of bleach or liquid chlorine anyway because the pucks raised the CYA so high that you couldn't use them to raise the FC high enough to compensate and now you have a big, fat algae bloom and you're going to have gallons and gallons of bleach every day to kill it.

But if you dilute 12.5% LC half and half with fresh water you may be getting 6% at a lower per gallon cost than even in the grocery stores. Nothing wrong with saving a few bucks! Why bother? Because at 12.5% LC is highly unstable and will break down into lower concentrations and you'll lose the edge. But if you dilute it yourself, you'll have 6% and that's got a lot longer shelf life--but you'll still want to keep it shaded and cool.