What Concentration of Dichlor does the Pool Calculator use?

[Puffin]

I noticed that the Dichlor seems to come in concentrations other than 100%, for example, Aqua Chem Shock Plus is 58.2% Sodium Dichloro-s-triazinetrione (yea I have the bottle in front of me :-D )

If he pool calculator says add say 16oz of dichlor, how much do I add? Is it expecting 58.2% or 100%, or another concentration?

 

[AnnaK]

Re: What Concentration of Dichlor does the Pool Calculator u

From a very quick search I found that "Aqua Chem Shock Plus, [is] a shock, buffer, clarifier, and flocculant all in one." Other dichlor products have something like 56% available chlorine and are 99% dichlor. My best guess is that when the Pool Calc suggests dichlor, it means the plain product, not one that has additional components like Aqua Chem Plus.

 

[JasonLion]

Re: What Concentration of Dichlor does the Pool Calculator u

Pool Calculator is assuming 99+% dichlor, 56% available chlorine.

If you want to convert a quantity to Aqua Chem Shock Plus, divide the amount Pool Calculator says by 0.58. So 16 oz in Pool Calculator becomes 27.5 oz of Shock Plus.

As a general rule it is best to avoid combo products like that one. It is better and less expensive to add the specific chemical you need instead of adding several things at once in proportions that you have no control over.

 

[madwil]

Re: What Concentration of Dichlor does the Pool Calculator u

agree with Anna, the other stuff is probably not needed; but
JasonLion will probably have to answer that question as to what concentration in the calculator- it's ultimately based on what he programmed the calculator with!

Or he can type faster than me...

 

[Puffin]

Re: What Concentration of Dichlor does the Pool Calculator u

Where do you folks normally buy just straight Dichlor? Pool store like Leslies? I don't remember seeing 100% dichlor at Walmart or Home Depot.

I'm in one of those unique situations where I need both stabilization and sanitation. My pool is being refilled, so I have no CYA or FC.

 

[Puffin]

Re: What Concentration of Dichlor does the Pool Calculator u

Pool Calculator is assuming 99+% dichlor, 56% available chlorine.

This... ugh, I got confused with 56% available chlorine vs 56% concentration. Thank you guys again for clearing that up.

Ok, so I'd still like to get some Dichlor. I'd love to hear your suggestions on where to (or best place) to buy Dichlor.

 

[JasonLion]

Re: What Concentration of Dichlor does the Pool Calculator u

I often see it at Home Depot. Leslie's certainly has it. The labeling can be confusing because it is available under many different names and they don't always list the concentration or add misleading numbers like the 56% available chlorine, which really means 100% dichlor.

 

[chem geek]

Re: What Concentration of Dichlor does the Pool Calculator u

This thread talks about this product where this MSDS does indeed show "Sodium dichloro-s-triazinetrione" as 58.2%, but the product that is nearly 100% in The Pool Calculator is the more commonly sold dihydrate form which at 100% "Sodium dichloro-s-triazinetrione dihydrate" is technically identical to 85.9% "Sodium dichloro-s-triazinetrione" with 14.1% water. So this product does seem to have a lot of filler in it. If you were to use The Pool Calculator, then you would divide the quantities by 58.2%/85.9% = 0.678

By the way, the more common dihydrate form of Dichlor is 55.4% Available Chlorine while the anhydrous Dichlor is 64.5% Available Chlorine. However, as shown in this thread the anhydrous pure Dichlor is more reactive and is a Class 3 oxidizer compared to the dihydrate form of Dichlor which is a Class 1 oxidizer. So almost all of the Dichlor sold at the retail level is the dihydrate form of Dichlor.

 

[dewdrop519]

Re: What Concentration of Dichlor does the Pool Calculator u

I've been having the same questions about Dichlor. I found two different Aqua Chem products at K-mart this morning, so I bought both then came home and found this thread. One is the Shock Plus discusssed above, so I won't use that. But I also found AquaChem "Small Pool Sanitizer" which is 99% Sodium dichloro-s-triazinetrione and 1% other ingredient (??). Available chlorine is 55%.
Is this okay to use? Do I need to adjust the pool calculator amount for the 1%?
It's a 2lb canister of small granuals. The label says its for small vinyl pools up to 1000 gallons. (ours is 1718 gallons). We just set up the pool and filled it and have been adding bleach for 2 days, but its still too chilly to swim.

 

[chem geek]

Re: What Concentration of Dichlor does the Pool Calculator u

Aqua Chem Balanced for Clean Pools Small Pool Sanitizer is 99% Sodium dichloroisocyanurate dihydrate. If what you have shows a labeling of 99% Sodium dichloro-s-triazinetrione (which is a synonym for sodium dichloroisocyanurate), then their labeling is wrong and missing the "dihydrate". The reason is that 99% of pure anhydrous dichlor (i.e. without the "dihydrate) would be 64% Available Chlorine while 99% of dichlor dihydrate would be 55% Available Chlorine which is what they show. As I noted above, almost all Dichlor sold for pools and spas is the dihydrate form and that is what the Pool Calculator uses, though it does assume essentially 100% purity (so 99% is clearly close enough).

So yes, this product is OK to use and no, you don't need to adjust The Pool Calculator for the 99% vs. 100%. None of your measurements or assumptions will be anywhere near 1% precision so don't worry about that.

Now I assume you intentionally are trying to raise the Cyanuric Acid (CYA) level in your pool because for every 10 ppm Free Chlorine (FC) added by Dichlor, it will also increase CYA by 9 ppm. If that was not your intention and you already have enough CYA in your pool, then you should not use Dichlor. Since you just filled the pool, however, it does sound like you are wanting to add CYA and Dichlor is one way to do that (over time), but if you've been adding bleach to this vinyl pool without any CYA in the water, then that's not good (the chlorine would be too strong and would break down too quickly in sunlight). If you don't add pure CYA to the pool right after filling it, then you could use Dichlor as your initial chlorine source, but keep track of how much you add so as not to overdo the CYA level and then switch to bleach once your CYA target is reached.

 

[dewdrop519]

Re: What Concentration of Dichlor does the Pool Calculator u

Okay the label actually does say 99% "Sodium dichloro-s-triazinetrione dihydrate" . And you're correct we need to get some CYA in the pool. My husband was a little anxious to fill the pool so we added bleach per the pool calculator until we got the recommended Dichlor. We didn't want to let the water sit with nothing for a few days.... So I'm going to read the pool school again and use the calculator, but it sounds like we should add only the AquaChem for the next 4 nights (with no bleach) and then we'll switch back to bleach.
I really appreciate all the help on this forum!

 

[chem geek]

Re: What Concentration of Dichlor does the Pool Calculator u

OK, that's fine. A couple of days with bleach isn't serious and is fine while you waited for the Dichlor. You're doing great!