Suncoast Gold liquid chlorine strength question

[ramblinwreck001]

I've been using this Suncoast Gold liquid chlorine to chlorinate my pool, as this is the most convenient LC option for me locally.
I was under the impression (from folks in store) this is 12% strength, and this page (describing the above product) says "Provides 10-13% available chlorine"

However, I just looked the label on my actual jug and it says 10.5% sodium hypochlorite:


Interestingly, I noticed someone complaining about this apparent discrepancy on a review of our local Pinch A Penny store, and here was the owners response:

Our liquid chlorine is represented to us to be exactly in line with our supplier to be "12% by trade and labeled and sold 10.5% Sodium Hypochlorite by weight. They are the same thing just different terminology.

Two questions:
1. Is that a legit explanation?
2. What % should I use in the PoolMath app when using this product?

 

[mknauss]

Weight Verses Trade- Understanding Chlorine Concentrations in Different Sources - Further Reading

www.troublefreepool.com

 

[ramblinwreck001]

Thanks. That helps, but I'm still not 100% sure on what I should use for PoolMath.

Key point from the page you linked seems to be:

Note how pool chlorinating liquid is sold as Trade % while laundry bleaches are sold as wt%.

OK, that part is clear.
So if I use 7.5% disinfecting Clorox from the grocery store, it is 7.5% by weight, and I enter "Bleach Percentage" = 7.5% in PoolMath. No questions there.
But if I use this Suncoast LC product (12% by trade, 10.5% by weight), then I should actually enter 10.5% for Bleach Percentage in PoolMath? Correct? (if so, I've been using it wrong...)

Asked another way, is it correct to say the PoolMath app always expects bleach % by weight? If so, that isn't explicitly stated in the app (if it is I've missed it), though I do notice it is called out on the old web calculator page.

 

[mknauss]

Enter Trade % for Liquid Chlorine.

 

[ramblinwreck001]

Now I'm thoroughly confused.
Why would I use Trade % for one and Weight % for the other?
I understand they're marketed and sold using different terminology, but when it comes to FC math/calculations, shouldn't we be using the same units for both?
And this begs the question, if they're different (and should be entered differently), wouldn't it be a good idea to have a separate "Liquid Chlorine" (vs "Bleach") category in PoolMath? I don't see anything like that and have just been using Bleach.

 

[mknauss]

Right now, the app shows 'bleach'. That is likely to change.

The app handles the difference. It is just how things are labeled, so the app manages the differences in the back ground.

 

[ramblinwreck001]

Right now, the app shows 'bleach'. That is likely to change.

The app handles the difference. It is just how things are labeled, so the app manages the differences in the back ground.

How can the app do that?
If I enter "Bleach", it doesn't know whether I'm using Clorox or LC.
When I use 7.5% (by weight) Clorox, I'm entering Bleach = 7.5%
When I use 12% (by trade, actually 10.5% by weight) LC, you're telling me to enter Bleach = 12%.
How does the app know to interpret those two entries differently?

 

[mknauss]

By the %. Bleach is not sold in anything greater than 8.25% weight (and that is not likely to be available anymore). Liquid chlorine is not sold in anything under 10% trade. So it knows.

And we are not talking rocket science here. Being off a few tenths of a % is not critical in a body of water several thousands to several 10's of thousands in volume.

 

[Newdude]

Either way, 12.5% degrades so quickly that it rarely is. Many times it's 10% or 11% by the time it makes it in the pool unless you buy small quantities from a wholesale supplier.

Always test after to ensure you got enough FC from that batch, or add a few extra glugs for good measure.

 

[ramblinwreck001]

By the %. Bleach is not sold in anything greater than 8.25% weight (and that is not likely to be available anymore). Liquid chlorine is not sold in anything under 10% trade. So it knows.

OK, so you're saying PoolMath interprets the entered % differently based on how big the % number is. If you enter 10% or larger it assumes you're using LC and assumes you have entered the % by trade, otherwise it assumes you're using bleach and assumes you're entering % by weight. Would be a nice enhancement for the app to actually say that, or provide separate categories for "Bleach % by weight" and "LC % by trade".

And we are not talking rocket science here. Being off a few tenths of a % is not critical in a body of water several thousands to several 10's of thousands in volume.

Indeed. I'm not suggesting otherwise. I'm simply new here and trying to understand how to use the app correctly.
I'm already dealing with a lot of unknowns in a pool I've just taken ownership of, so I'd like to eliminate this one.

 

[ramblinwreck001]

Either way, 12.5% degrades so quickly that it rarely is. Many times it's 10% or 11% by the time it makes it in the pool unless you buy small quantities from a wholesale supplier.
Always test after to ensure you got enough FC from that batch, or add a few extra glugs for good measure.

Thanks, and will do. I had already spotted the degradation issue from this page. Here's in Central Texas were hitting triple digits every day, so after 8 days (which is how long it takes me to use 2.5 gallons) I'm already under 10%, and that's assuming it was perfectly fresh when I got it which is probably isn't.

 

[Newdude]

Personally I'd assume 10% is 10%, and 12.5% is also 10%, unless proven otherwise. More often than not i wouldn't care to bother proving otherwise, and if the 12.5% was a little more than 10%, I'd see the gain on the following day.

 

[kellyfair]

I use same brand, and when I put 10% into PoolMath, I found that I overshot it a bit. Now that could be caused by a few things, like being slightly off in my total gallons for my pool. But I found I was closer to expectations by changing to 12.5% in PoolMath.

And there you have my very unscientific method of determining the strength of my Chlorine.

 

[ramblinwreck001]

I use same brand, and when I put 10% into PoolMath, I found that I overshot it a bit. Now that could be caused by a few things, like being slightly off in my total gallons for my pool. But I found I was closer to expectations by changing to 12.5% in PoolMath.

That's interesting! I've experienced something similar, which is sort of how I ended up here with this thread.
I've found that using 12% in PoolMath is working really well for me, two reasons:

1. Using 12% is giving me surprisingly (to me, as a noob) accurate results. EXAMPLE: I measure FC of 5 one evening. PoolMath says I need 32oz of 12% LC to reach target of 7. So I add 32oz (yes, I'm measuring for now, I know many of you don't). One hour later I test and it is right on the money at 7. It's nice to have confidence that my LC additions are doing exactly what I expect them to!

2. Using 12% means that PoolMath suggests nice even 4oz increments for my LC additions, for example (my FC target is 7):

• 32oz 12% LC to take FC from 5 to 7
• 24oz 12% LC to take FC from 5.5 to 7
• 16oz 12% LC to take FC from 6 to 7

Now I know my pool isn't exactly 15K gallons (that number is based on what prior owner thought it was), and I know my LC likely isn't 12% (discussed above), but for whatever reason using 12% in PoolMath is working so I'll stick with that for now.

 

[Newdude]

but for whatever reason using 12% in PoolMath is working so I'll stick with that for now.

Never look gift FC in the mouth.

The key is to adapt as necessary.

 

[SQLGeek]

Sounds like 12% is working well for you. I personally use 10% in Pool Math with the Suncoast Gold and it seems to be fairly dialed in for my pool. I'm glad I found this thread as I wasn't aware of the difference of trade vs weight.

I agree with you that I have been impressed with the Pool Math app which makes the $7.99 a year to be a no brainer.