R-0009 sulfuric acid .12N

[smackdab]

What does R-0009 sulfuric acid .12N equate to in muriatic acid?

In other words, as far as lowering the pH and carbonate level, R-0009 = 5% MA?

 

[JamesW]

0.12N sulfuric acid is equivalent to about 0.437% HCl.

 

[Razorhog]

I'm no chemist but I don't think sulphuric acid is a good idea. Could a Chem geek chime in?

 

[JamesW]

I don't think that they want to use sulfuric acid in the pool.

However, I don't know why they asked.

Some people use sulfuric acid in their pool. However, I wouldn't use it due to the sulfate content.

 

[smackdab]

I use muriatic acid in my pool. I was wondering so I can estimate the pH and TA drop for the R-0009 drops for the drop based borate test.

 

[JamesW]

1 drop of R-0009 in 25 ml pool water drops the TA by 10 ppm.

 

[smackdab]

Well that certainly makes sense thinking about the 25ml TA test.

So if you have a TA of 100, you need at least 10 drops of R-0009 to remove all of the carbonate alkalinity from the sample?

That should move the pH from 7.8 to ~6.1. Is that a low enough pH level for the drop based borate test to work? Maybe add a drop or two from the figure above?

 

[smackdab]

Just thought, there is more than carbonate alkalinity involved in "Total Alkalinity". Not sure my question above makes sense now.

 

[JoyfulNoise]

Well that certainly makes sense thinking about the 25ml TA test.

So if you have a TA of 100, you need at least 10 drops of R-0009 to remove all of the carbonate alkalinity from the sample?

That should move the pH from 7.8 to ~6.1. Is that a low enough pH level for the drop based borate test to work? Maybe add a drop or two from the figure above?

Just thought, there is more than carbonate alkalinity involved in "Total Alkalinity". Not sure my question above makes sense now.

I use muriatic acid in my pool. I was wondering so I can estimate the pH and TA drop for the R-0009 drops for the drop based borate test.

No, I was incorrect about that.

The purpose of the R-0009 in the test is simply to set the pH below the titration point of borate/diol reactions. There's no need or purpose to consume any alkalinity. In fact, as it was explained to me (and finally made a lot of sense after looking at the numbers in the spreadsheet), it doesn't matter at all if there's any other buffers around (carbonates or cyanurates) as it is a titration test which is only counting the number of drops needed to restore the pH to it's previous level AFTER the mannitol is added. This is why you start at a low pH and get a yellow color from the BTB. Then you add the R-0010 until you get the first stable baby blue color. At this point, the blue is your starting point of the reaction. Then you add the mannitol and the sample turns yellow again from the pH drop. Then you add the R-0010 while counting the drops until you return to the original blue color you had. So it doesn't matter at all what the other buffers are doing since the pH is only affected by the addition of the mannitol and the presence of borates.

My apologies for the confusion...

 

[JoyfulNoise]

And yes, sulfuric acid is much too dangerous to use around a pool. Even though it's acidity is on par with MA, sulfuric acid can readily attack and destroy skin tissue because it is a very strong dehydrating agent as well as a powerful oxidizer. Because it's heat of hydration is very large, it can cause secondary burns as it absorbs water. It can easily destroy proteins and lipids in the skin. If you pour concentrated sulfuric acid in water at a fast enough rate, you will cause the water to boil rapidly and to the point of creating a hazardous over-boil with splashing (don't ask how I know that...). Honestly the stuff should never be used outside of a fume hood and within inches of a safety shower and eye wash.

I once got a very tiny droplet of sulfuric acid on my skin (near the wrist between where a safety glove would end but before my shirt sleeve began). IT HURT LIKE HE _ _!!! and left a nice burn and tiny scar even though I rinsed the area immediately. I've also gotten full strength MA on my skin with no damage at all.

 

[smackdab]

Thanks for clarifying. The borate drop test thread is kind of hard to follow and understand. I've added 50 ppm borax to my pool and am awaiting my BTB and mannitol powder to try the test. I do understand how to do the test but there was some things left unclear, such as:

1) Adding more R-0007 if the FC is high. What constitutes "high"? I think I answered that one here.
2) Adding more R-0009 if the TA is high. What constitutes "high"? My TA is low enough (70) that I'm not worried about having to add more R-0009 but would like to know a "drop number per TA level" or something to go by so you know you have put enough R-0009 in the sample.

So when adding R-0009, you're only worried about dropping the pH to a 6.0 since that is yellow for BTB?........or what pH do you need to go to below the titration point?

 

[JoyfulNoise]

I'll go back and simplify the instructions in that post. I tried writing it to cover all the bases and so it got too long.

Yes, you only need to add enough R-0009 to get the pH to the yellow point of the BTB. So I was actually thinking about it and I don't see why one can't reverse the two steps - add the BTB before adding the R-0009.

So the new process would look like this -

1. Add the R-0007
2. Add the BTB
3. Add the R-0009 to drop the pH to yellow
4. Add the R-0010 to raise the pH just up to the baby blue point.
5. Add the mannitol (color should turn back to yellow).
6. Add the R-0010 and count drops until the baby blue color is restored.

The only hitch is this - the R-0009 and R-0010 are very closely matched and so one drop of one will neutralize one drop of the other. So when adding the R-0009 in step 3, you want to go a drop or two beyond the yellow point so that you're using more than one drop of R-0010 in Step 4 to get that baby blue color. It's really important to get that first blue hue because the transition from greenish-yellow to baby blue is the steepest part of the titration curve AND THAT'S WHAT YOU WANT. The steepest point of the titration curve represents the equivalence point of the the reaction where the moles of the standard solution (titrant or R-0010) equals the moles of the unknown solution (analyte or borates).

See here - Titration Fundamentals - Chemistry LibreTexts

I will test the revised procedure above since I tested borates yesterday and let you know how it works.

 

[smackdab]

Thanks for updating the instructions. I also was wondering why you couldn't add BTB before adding R-0009 to visualize the yellow transition. The proteam supreme test instructs the user to add more acid (R-0009) after adding BTB if it does not turn yellow, if I'm reading it correctly, so I assume that will work. I will try the updated instructions when I get to test.


If R-0009 = 0.437% MA and your test results: pH 7.8, TA 60, Borates ~50.
Your instruction says for 50ml sample use 8 drops of R-0009 which should drop your pH to 6.0, right on the transition of being yellow.
9 drops R-0009 drops pH to 5.9,
10 drops R-0009 drops pH to 5.8,
12 drops R-0009 drops pH to 5.7,
13 drops R-0009 drops pH to 5.6.
That is if all my calculations pan out, my drop rate is 20 drops per ml. Have you had any trouble testing sitting right at the yellow transition point of the BTB?


If all I do is change the TA level (still with 50ml sample):
TA 70: 9 drops of R-0009 to drop the pH to 6.0.
TA 80: 10 drops of R-0009 to drop the pH to 6.0.
TA 90: 11 drops of R-0009 to drop the pH to 6.0.
TA 100: 12 drops of R-0009 to drop the pH to 6.0.


Looks like the TA level could dramatically change how many drops of R-0009 one ends up using. Maybe your instruction should say use R-0009 until the straw color, then add a drop or two. That will eliminate the confusion of using 8 drops of R-0009 because you know someone with a TA of 80 or 90 will use 8 drops of R-0009, or even I would have with a TA of 70.

Also if I could suggest listing a recommended size of mannitol and BTB to buy and the shelf life of them. I received my 4 oz of mannitol today and the bottle is alot bigger than I thought is was going to be. I'm not sure how many tests it will actually do, but it looks like 3-4 years worth of borate tests.

 

[JoyfulNoise]

No problems. Remember that the first yellow point is just setting the solution pH low enough to see the blue when you bring it up with the R-0010.

I have found that when I use 8-10 drops of R-0009, one drop of R-0010 gets you to the yellow-green color and then the second drop gets you to the baby blue. So going lower in pH with R-0010 just means adding (and wasting) R-0010.

As I say in the instructions, it would be nice if the titrant was a little less concentrated as it would make the transition a bit easier to see. If I had my own chem lab, all of the right standard solutions could easily be whipped up...but, alas, those days are over....

 

[JoyfulNoise]

I will make the changes you suggest

 

[smackdab]

No problems. Remember that the first yellow point is just setting the solution pH low enough to see the blue when you bring it up with the R-0010.

I have found that when I use 8-10 drops of R-0009, one drop of R-0010 gets you to the yellow-green color and then the second drop gets you to the baby blue. So going lower in pH with R-0010 just means adding (and wasting) R-0010.

As I say in the instructions, it would be nice if the titrant was a little less concentrated as it would make the transition a bit easier to see. If I had my own chem lab, all of the right standard solutions could easily be whipped up...but, alas, those days are over....

Ok, I see.

 

[JoyfulNoise]

Ok, I see.

The mannitol and BTB should last quite some time. I have no firm numbers on how long they will last but mine are both at least 18 months old and they still work fine.

 

[Patrick_B]

And yes, sulfuric acid is much too dangerous to use around a pool. Even though it's acidity is on par with MA, sulfuric acid can readily attack and destroy skin tissue because it is a very strong dehydrating agent as well as a powerful oxidizer. Because it's heat of hydration is very large, it can cause secondary burns as it absorbs water. It can easily destroy proteins and lipids in the skin. If you pour concentrated sulfuric acid in water at a fast enough rate, you will cause the water to boil rapidly and to the point of creating a hazardous over-boil with splashing (don't ask how I know that...). Honestly the stuff should never be used outside of a fume hood and within inches of a safety shower and eye wash.

I once got a very tiny droplet of sulfuric acid on my skin (near the wrist between where a safety glove would end but before my shirt sleeve began). IT HURT LIKE HE _ _!!! and left a nice burn and tiny scar even though I rinsed the area immediately. I've also gotten full strength MA on my skin with no damage at all.

I want to emphasize to anyone reading this in the future. What Matt says about not using SA in a pool under any circumstances cannot be over stated. It's much too dangerous to have anywhere near your family or pets. I know first hand how quickly and badly it can injure you, and I could share more than one truly horrific story of exposure but that has no place here. As well, SA has no place in anyone's pool care regimen.