Different types of Dichlor and Pool Math

[easttn]

Just realizing there are a few different percentages of Dichlor products.
You have:
99% Sodium Dichloro-s-Triazinetrione Dihydrate (55% Available Chlorine)
99% Sodium Dichloro-s-Triazinetrione (62% Available Chlorine)
99% Sodium Dichloro-s-Triazinetrione (56% Available Chlorine)
63.05% Sodium Dichloro-s-Triazinetrione ( ? % Available Chlorine)
58.2% Sodium Dichloro-s-Triazinetrione ( ? % Available Chlorine)

First question: I cant find the % of Available Chlorine for the bottom two. Ive looked at alot of product labels at kellysolutions.com and cant find anything on those. Anyone know exactly what they are?
Second question: Which one is Pool Math using since it only shows "Dichlor" in the menu?

 

[chem geek]

In practice there are really just two kinds of Dichlor and the most common one by far is the dihydrate version. If it were 100% pure then it would be 55.4% Available Chlorine, but since most Dichlor products are 99% pure then it's around 55%. Dichlor products that say 56% are really 55% Available Chlorine. Technically, this dihydrate Dichlor is exactly the same as a combination of 85.9% anhydrous Dichlor with 14.1% water.

The other form of Dichlor is anhydrous, but it is far less common since it is a Class 3 oxidizer (as shown in the thread National Fire Protection Association (NFPA) Ratings) so is much more susceptible to sustained burning in a fire. If it were 100% pure then it would be 64.5% Available Chlorine, but since it's usually 99% pure then it's around 64%.

Some other Dichlor products aren't pure at all and contain other ingredients such as non-chlorine shock. Perhaps those are the last two you showed on the list or it might be that someone got mixed up between weight % and % Available Chlorine on the MSDS.

PoolMath assumes Dichlor dihydrate since that is by far the most common. If you use an anhydrous Dichlor product then multiply what PoolMath tells you by 55 divided by the % Available Chlorine of the product so for normal anhydrous this ratio is 55/64 = 0.86

 

[easttn]

The 58.2% Sodium Dichloro-s-Triazinetrione is the one that sits on the shelf at Walmart by the name of Aqua Chem Shock Plus. I saw several types with 63.05% Sodium Dichloro-s-Triazinetrione at kellysolutions.com and figured it was pretty common but I guess I was wrong. Thanks for the explanation.

 

[chem geek]

As noted in this link that is not a Dichlor-only product. They don't say what the other ingredients are, but the package says "Clarifier Enhances Filtration" so it at least has a clarifier in it. This MSDS gives more detail where the additional ingredients include 15-25% sodium persulfate, 5-15% aluminum sulfate, and 5-15% Boron salt. The sodium persulfate is similar to non-chlorine shock (potassium monopersulfate) except it is more irritating and is actually a minor component in MPS products. The aluminum sulfate is an alum floc so is what is used for clarification. The Boron salt is probably sodium tetraborate pentahydrate which raises the pH so balances the net acidity of the Dichlor (or it's boric acid which is only slightly acidic) and is a mild algaecide (though they don't claim the product as an algaecide).

 

[easttn]

I have about half a box of the Aqua Chem Shock Plus that I use time to time to raise CYA. I looked at the box and the bags and it doesnt say anything about a clarifier. I guess they cant make up their mind what they want to tell you about the product.