Is Smell an Indicator of Potency of Bleach?

[KatyTXPoolOwner]

I might have found a good source of 12.5% bleach in my area. It comes out to about $4.20/gallon (about .26/oz of chlorine). I say "might" because I'm not sure if it's fully 12.5%. I purchased 16 gallons 4 days ago. They are in my garage stored in white gallon jugs, enclosed in a yellow plastic case, and away from direct sunlight. The caps are tight.

Question: I poured some into the pool this evening and smelled the bottle before doing so. It hardly smelled at all - it was almost odorless. It is Hasa Sodium Hypochlorite and I buy it from a middle-man. Should I be concerned that it is nearly odorless?

Thank you.

 

[Isaac-1]

Bleach itself has very little scent, that "chlorine smell" that people associate with poorly maintained swimming pools is really Combined Chlorine byproducts, in the case of smelling bleach and getting those combined chlorine scents, most of what you are really smelling is the byproduct of the chlorine reacting with the linings of our nasal passages.

 

[KatyTXPoolOwner]

So smelling it directly out of the bottle (and taking a pretty good whiff) and it should be nearly odorless?


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[YippeeSkippy]

I don't know about odorless since I can smell it when pouring into the washing machine. I'd say go to PoolMath and get an amount to raise your FC by 2ppm, then add that and retest in a while. See if it hit the mark or not?

 

[pooldv]

Yeah, good idea, I'd skip sniffing the bleach.

 

[camueller]

To answer the question, even if there was a difference in smell based on concentration, I highly doubt a human's nose could decipher that difference between an 8.25% and a 12% bleach.

 

[Teald024]

The smell test is not the preferred method and many would claim it to be frowned upon. Many would choose to not inhale it on purpose, LOL. If you're really concerned about the strength you could always dilute a known volume and then perform a test on it using your test kit. A close enough value would be to just pour it in your pool and see how much it raised the FC level.

.

 

[borjis]

Just dose the pool when ready and test it. That's the only way to know for sure.

12.5% does lose potency quicker than a lower concentration though. (when stored)

 

[Patrick_B]

So smelling it directly out of the bottle (and taking a pretty good whiff) and it should be nearly odorless?

Although I dont suggest it either, the answer is yes. Even brand new drums of 12.5% have just as little odor. This was a shocking revelation to me many years ago, but its absolutely true.

 

[KatyTXPoolOwner]

Thank you everyone for your input. Of course, I don't make it a habit of smelling bleach or any other chemicals but I appreciate the comments suggesting it's not a good idea.

I've been conducting some Test / Add / Test / Test exercises over the past couple of days, all of which were completed after the sun went down and before the sun came up the next morning, and can't seem to get any consistency. Pool is crystal clear and there are no other issues.

In addition to the readings below: CH 375 TA 60 CYA 45 BOR 40 (BOR based on previous pool store reading)

Wednesday
8:10pm FC 4.5 CC 0
8:15pm Added 47 oz of 12.5% bleach (targeting 6.5 per Pool Math)
10:40pm FC 5.5 CC 0

Thursday
7:00am FC 5.5 CC 0 pH 7.6
8:00pm FC 4.0 CC 0
8:15pm Added 47 oz of 12.5% bleach (targeting 6.0 per Pool Math)
9:40pm FC 5.5 CC 0

Friday
7:15am FC 5.5 CC 0 pH 7.7

After adding the same amount (47 oz) from the same bottle of 12.5% HASAChlor I see either a 1ppm rise or 1.5ppm rise in FC (should be 2ppm per PoolMath). Does that make sense? Perhaps I should be more sensitive with my testing (.2 increments of FC instead of .5 increments). Can someone shed some light on how to do that?

Thank you!

 

[pooldv]

Use a 25ml water sample and then count each drop as 0.2 ppm FC. There are two main variables, pool gallons and chlorine potency. The chlorine potency will always vary somewhat with age and batch. If you feel pretty good about your pool being 23k gal or you might need to work on dialing that in a bit if it is just a swag.

 

[KatyTXPoolOwner]

I feel fairly confident about the size at 23k. I checked the water meter before and after the original fill and it was pretty close to that but, now I'm second guessing myself and memory. Is there a really accurate way to measure volume via chemical concentration? I would think that if the strength of a given chemical was verified to be accurate, i.e., 12.5% bleach, then a Test / Add / Test approach would yield pretty accurate results. Is there a chemical and test procedure that others have used successfully?

 

[JoyfulNoise]

Yes, there is -

A Chemical Way of Calculating Pool Volume

But it uses up a lot of TA reagent.

 

[Cinic]

Sniffing should be reserved for flowers and glue.