Bleach is no longer cost-effective???

[beavis]

I am starting my new pool for the first time soon and I like the concept of using bleach for chlorination. However, unless my math is wrong, it looks like the cost-effectiveness of bleach has worsened dramatically in the last few years due to an increase in bleach prices.

Taking data from an excellent thread by chem geek here , a few years ago, the cost-effectiveness of various methods of chlorination was:

Trichlor Tabs/Pucks (3") ... $77 for 35 pounds so that's $2.20 per pound
Dichlor ... $104 for 40 pounds so that's $2.60 per pound
73% Cal-Hypo ... $120 for 50 pounds so that's $2.40 per pound
Lithium Hypochlorite ... $150 for 25 pounds so that's $6.00 per pound (from this website since Leslie's doesn't carry it online as far as I could tell)
12.5% Chlorinating Liquid ... $3.25 for 1 gallon from my local pool store (9.7 pounds -- product is 16% denser than water) so that's $0.336 per pound
6% Bleach ... $1 for 96 ounces (6.75 pounds -- product is 8% denser than water and 96/128th of a gallon) so that's $0.15 per pound

Notice how much less expensive per pound the chlorinating liquid is. It had better be because most of it is water, so what we really need to see is the cost per available chlorine and that is as follows:

Trichlor Tabs/Pucks ......... $2.20 / 0.915 = $2.40 but $3.83 when accounting for Washing Soda to adjust pH
Dichlor .......................... $2.60 / 0.554 = $4.70 but $5.73 when accounting for Washing Soda to adjust pH
73% Cal-Hypo ................ $2.40 / 0.724 = $3.31
Lithium Hypochlorite ....... $6.00 / 0.352 = $17.05
12.5% Chlorinating Liquid . $0.336 / 0.108 = $3.11
6% Bleach ..................... $0.15 / 0.057 = $2.63

However, in researching today, I find the following costs:

Trichlor = $2.29/lb
Dichlor=$3.29/lb
Cal-Hypo=$2.49/lb
6% bleach= $2.16 for 96oz = $.32 per lb (big increase vs other options)

Compensating for available chlorine:

Trichlor= $2.29 / 0.915= $2.50/lb or $3.93 w/acid compensation (assuming no change in washing soda price)
Dichlor= $3.29 / .551 = $5.93/lb or $6.96 w/ acid comp
Cal-Hypo=$2.49 /.724= $3.40/lb
Bleach = $.32/.057 = $5.61/lb

Given the above, it seems like Trichlor is the winner for those worried about high calcium levels, even considering that perhaps someday I will have to drain some water to reduce CYA.

Anyone have other thoughts?

[JasonLion]

If you hunt around, I am sure you can find a much better price than that for bleach. Costco was running about half that price if you bought a whole case the last time I looked, and WalMart around here is only a little more than Costco.

[beavis]

actually, I got the price from the costco website here

[ScottS]

I do have to agree with you somewhat as I was calculating this the other day. At WalMart I get a 182oz jug for $2.54 so that is definitely less than what you are finding.

However it has been a royal PITA purchasing the WalMart brand bleach. Half of the jugs I grab have busted seals on the top. So now when I purchase I end up having to open each jug before I put it in the basket. This is time consuming and frustrating at the same time. Now, the seals that are intact do not want to remove with the useless "pull tab". I end up cutting them off. It just seems to be much more of a hassle than it used to be.

On the other hand some of the other methods may seem cheaper initially but it's the side effects they cause that make it more costly and causes one to chase his tail. For instance the trichlor pucks are acidic plus they add stabilizer. Neither is a great option for me as my pH is constant and doesn't swing due to the fact that I chlorinate with bleach.

I guess I got off track a bit however it's all related. The cost may have gone up but I still think it allows maintaining crystal clear water very easily

-Scott

[aylad]

. Now, the seals that are intact do not want to remove with the useless "pull tab". I end up cutting them off. It just seems to be much more of a hassle than it used to be.

I agree with you there--in fact, I've started leaving a butter knife outside near the pool just for that purpose!! Didn't notice it so much last summer, but then again our WalMarts had a hard time keeping the larger size jugs in stock.

Still worth it, though, once you get your water where you want it, it's really the easiest way to keep it there, short of SWG!

Janet

[chem geek]

Fortunately, I am able to get 12.5% chlorinating liquid from my local pool store for $3.00 per gallon (before tax) which actually went down in price from last year and is equivalent to $1.11 for a 96-ounce (3/4 gallon) jug of bleach. They also reuse the bottles which is better than recycling.

[sunofthebeach]

Beavis,

I came to the same conclusion several years ago. It is also too inconvienant to buy bleach so often.

I bought 40 pounds of trichor at cosco for $89 and that will last all swim season. I shock with bleach and I open my pool using bleach.

I always open my pool to 0 cya every season, so I am not concerned about adding cya through the season.

[chem geek]

If one has a shorter swim season, a smaller pool, a sand filter backwashed weekly, summer rains with overflow, winter rains or other reduction of CYA over the winter, then one can sometimes get enough water dilution to manage using Trichlor pucks/tabs.

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm. Even with a low 1 ppm FC per day chlorine usage, after 6 months this is over 100 ppm CYA if there is no water dilution. So this wouldn't work very well for those with cartridge filters that don't get backwashed, dry summers with no rain, larger pools, and longer swim seasons. My pool falls under most of those criteria (cartridge filter so no backwashing, dry summers with almost no rain, 16,000 gallon pool, 7-month swim season).

Every situation is different, and BBB is about understanding what is going on and doing what is appropriate for YOU armed with information and knowledge to make an informed decision.

[CarlD]

I...

Every situation is different, and BBB is about understanding what is going on and doing what is appropriate for YOU armed with information and knowledge to make an informed decision.

Precisely!

Generally, we suggest B-B-B and avoiding Tri-Chlor pucks. People who WATCH their CYA and pH levels, and know exactly where they want to be, can use them very effectively.

But people who don't pay attention to these things or follow pool store advice get into trouble with pucks that using Bleach/Liquid Chlorine don't because the bleach doesn't impact pH or CYA .

(Chem_Geek has some great posts on how the action of bleach both raises and lowers pH ending in...a zero-sum effect!)

Ultimately, the BEST way to save money on your pool care is with knowledge and information--and we have lots of it in our stickied posts-- everything you need for simple pool maintenance and trouble-shooting plus a lot more.

[pedsrn]

Just purchased Clorox 182oz @ Sam's Wholesale for $7.18 for a case of 3. $2.39 a bottle. Clorox brand does not have those pesky "safety" tabs.