Can Sometime Confirm?

[TomC]

Hi All,

Well, we tried our drop test tonight and wooooohooooo, it is at least a million times more accurate that the test strips!!!!!

Now that we have numbers though, well we have questions too. Here are the details, as indicated by the drop test :

Tub Size : 418 gallons

Water Temp : 101

CH : 110ppm

TA : 60ppm

pH : 8.0

Our pH looks high so we used the drip kit and added one drop of whatever and it dropped to 7.6. When we get a chance, we will investigate what that one drop represents (no doubt the manual will tell us that one drop equates to so much of some compound required to lower the pH to 7.6)

Using the pool calculator site, it would appear that we should raise our TA to 130. Again, we are new to the drip tests and could very well have misused/misread the results of the pool calculator. Assuming though that we did everything right, is a TA 0f 130 really high (it sounds high to us but not sure why it sounds high, just does)?

Here are the questions, should we lower the pH to 7.6 before we increase the TA? When we get the pH to 7.6, do we then raise the TA to 130? Is a TA of 130 really high?

Believe it or not, we are starting to understand water chemistry but we want to confirm these numbers with the experts (you guys) first.

Thanks...Tom

[quantumchromodynamics]

If your tub contains any plaster or grout then you would want a balanced Saturation Index. You could do that by keeping a slightly higher pH (7.6 to 7.8 instead of 7.4 to 7.7) and a higher calcium level.

If it is all plastic then you don't need or want a positive SI. Either way, an alkalinity of 130 is not what you want.

If you don't have plaster or grout to protect from dissolving, add some dry acid (0.49 ounce weight) or muriatic acid (0.37 fl. oz.) to lower your pH. Keep adjusting your pH until it stays where you want it. Once the pH stabilizes, that's where you need to keep the alkalinity.

[TomC]

Hi,

Thanks for the reply.

Being new to water chemistry, it will take some digesting on our part of figure it out. However, I am confused on how to bring our TA number down (and not have the other numbers go out of whack). For example, if our CH is set (at 110) and we want a pH in around 7.6, does our TA number not have to stay at 130 to make it all work?

Sorry, it could be our "understanding" of the process.

Thanks...Tom

[quantumchromodynamics]

There is no reason for your alkalinity to be at 130. Your alkalinity should be wherever it keeps your pH where you want it.

Your alkalinity will probably need to be kept at about 50 to 60 to maintain your pH at 7.6. All you should do now is add some acid to lower your pH. Adding acid will cause your alkalinity to drop.

Adding 30 to 50 ppm of borates (From boric acid or Borax) will help stabilize your pH.

[OttawaGreg]

Hi All,

Well, we tried our drop test tonight and wooooohooooo, it is at least a million times more accurate that the test strips!!!!!

Now that we have numbers though, well we have questions too. Here are the details, as indicated by the drop test :

Tub Size : 418 gallons

Water Temp : 101

CH : 110ppm

TA : 60ppm

pH : 8.0

Our pH looks high so we used the drip kit and added one drop of whatever and it dropped to 7.6. When we get a chance, we will investigate what that one drop represents (no doubt the manual will tell us that one drop equates to so much of some compound required to lower the pH to 7.6)

Using the pool calculator site, it would appear that we should raise our TA to 130. Again, we are new to the drip tests and could very well have misused/misread the results of the pool calculator. Assuming though that we did everything right, is a TA 0f 130 really high (it sounds high to us but not sure why it sounds high, just does)?

Here are the questions, should we lower the pH to 7.6 before we increase the TA? When we get the pH to 7.6, do we then raise the TA to 130? Is a TA of 130 really high?

Believe it or not, we are starting to understand water chemistry but we want to confirm these numbers with the experts (you guys) first.

Thanks...Tom

With those numbers I'd just drop the pH a bit using muriatic acid. You're in Ottawa West right, Kanata? Head to the new Home Hardware on Eagleson and they have it there at a decent price. Handle with care!

Your TA might come down a bit but that is supposed to be ok. I believe baking soda raises TA and doesn't effect pH (too much).

Greg

[TomC]

Hi All,

Well, we tried our drop test tonight and wooooohooooo, it is at least a million times more accurate that the test strips!!!!!

Now that we have numbers though, well we have questions too. Here are the details, as indicated by the drop test :

Tub Size : 418 gallons

Water Temp : 101

CH : 110ppm

TA : 60ppm

pH : 8.0

Our pH looks high so we used the drip kit and added one drop of whatever and it dropped to 7.6. When we get a chance, we will investigate what that one drop represents (no doubt the manual will tell us that one drop equates to so much of some compound required to lower the pH to 7.6)

Using the pool calculator site, it would appear that we should raise our TA to 130. Again, we are new to the drip tests and could very well have misused/misread the results of the pool calculator. Assuming though that we did everything right, is a TA 0f 130 really high (it sounds high to us but not sure why it sounds high, just does)?

Here are the questions, should we lower the pH to 7.6 before we increase the TA? When we get the pH to 7.6, do we then raise the TA to 130? Is a TA of 130 really high?

Believe it or not, we are starting to understand water chemistry but we want to confirm these numbers with the experts (you guys) first.

Thanks...Tom

With those numbers I'd just drop the pH a bit using muriatic acid. You're in Ottawa West right, Kanata? Head to the new Home Hardware on Eagleson and they have it there at a decent price. Handle with care!

Your TA might come down a bit but that is supposed to be ok. I believe baking soda raises TA and doesn't effect pH (too much).

Greg

Hi Greg,

Thanks for the tip. I think that I will just bring the ph down with a prodcut called "Ph minus", we got it from Arctic Spa. Once that stuff is done then I will start using the muriatic acid method.

Those drop tests really are quite accurate.

Cheerio...Tom

[Nitro]

Thanks for the tip. I think that I will just bring the ph down with a prodcut called "Ph minus", we got it from Arctic Spa. Once that stuff is done then I will start using the muriatic acid method.

pH Minus is Dry Acid. Either Muriatic or Dry Acid will work at lowering TA/pH. Careful using Muriatic Acid. Check out my "Lowering TA" link below for more info.

[TomC]

Thanks for the tip. I think that I will just bring the ph down with a prodcut called "Ph minus", we got it from Arctic Spa. Once that stuff is done then I will start using the muriatic acid method.

pH Minus is Dry Acid. Either Muriatic or Dry Acid will work at lowering TA/pH. Careful using Muriatic Acid. Check out my "Lowering TA" link below for more info.

Hey Nitro,

Thanks, thought that was what ph minus was.

We are slooooooowly starting to figure out water chemistry. According to our drop tests, the CH is 110ppm, ph is 8, and TA is 60ppm, tub Size : 418 gallons, water temp is 101. Should we just add the ph minus until it is in the 7.5 range? Should we fret over the TA at all?

From what I have read from your posts, ph just tends to naturally creep up. To deal with that, do we simply keep testing and bring it down as needed? I now understand that TA controls the amount of ph creep and was wondering if a TA of 60ppm would be enough to keep the ph in check.

Thanks...Tom

[Nitro]

Hey Nitro,

Thanks, thought that was what ph minus was.

We are slooooooowly starting to figure out water chemistry. According to our drop tests, the CH is 110ppm, ph is 8, and TA is 60ppm, tub Size : 418 gallons, water temp is 101. Should we just add the ph minus until it is in the 7.5 range? Should we fret over the TA at all?

From what I have read from your posts, ph just tends to naturally creep up. To deal with that, do we simply keep testing and bring it down as needed? I now understand that TA controls the amount of ph creep and was wondering if a TA of 60ppm would be enough to keep the ph in check.

Adjust TA until pH stays in range. You may need to drop TA to 50 ppm for that to happen. Just keeping adding a TBS of Dry Acid until your pH stays 7.6-7.8 with the jets/air on. Then make note of your TA. Afer you get your pH stable, add Borates to lock it in.

FYI, I just got my pH stable at 7.6 with jets/air running for an hour, with TA at 50ppm. I just added 50 ppm Borates. I'm going to have a nice, much needed soak tonight.

[quantumchromodynamics]

I now understand that TA controls the amount of ph creep and was wondering if a TA of 60ppm would be enough to keep the ph in check.

Total alkalinity only measures how much acid it takes to lower the pH. It doesn't really tell you how much base it would take to raise the pH. Total acidity tells you how much base it takes to raise the pH. If you know the components of total alkalinity, you can estimate the total acidity based on the equilibrium equations.

The primary components of total alkalinity and total acidity will be:

Carbonic acid, bicarbonates and carbonates.

Boric acid and borates.

Cyanuric acid and cyanurates.

Phosphoric acid and phosphates (If using a phosphate buffer).

A higher carbonate alkalinity will not help reduce pH rise. It will cause more pH rise. This is because at higher levels of carbonate alkalinity, there will be more carbonic acid which will outgas as carbon dioxide, which raises pH.

Adding about 20 to 30 ppm of cyanuric acid will help. This can be accomplished by using dichlor. After a cumulative use of about 3 ounces (weight) of dichlor or 30 ppm, your cyanuric acid should be about 27.

Dichlor is slightly acidic, so you would want the pH slightly higher than your target pH before adding dichlor so that the pH ends up exactly where you want it.

Adding 30 to 50 ppm of borates (From Borax or boric acid) will also help reduce pH rise.

You should maintain a Saturation Index of about -0.3 to 0.0. Adding cyanuric acid and borates will lower your CSI to below -0.3 at a pH of 7.6, so you would want to add some calcium to about 150.

I suggest that you keep the pH between 7.6 and 7.8. A higher pH helps reduce pH rise.

[OttawaGreg]

I now understand that TA controls the amount of ph creep and was wondering if a TA of 60ppm would be enough to keep the ph in check.

Total alkalinity only measures how much acid it takes to lower the pH. It doesn't really tell you how much base it would take to raise the pH. Total acidity tells you how much base it takes to raise the pH. If you know the components of total alkalinity, you can estimate the total acidity based on the equilibrium equations.

The primary components of total alkalinity and total acidity will be:

Carbonic acid, bicarbonates and carbonates.

Boric acid and borates.

Cyanuric acid and cyanurates.

Phosphoric acid and phosphates (If using a phosphate buffer).

A higher carbonate alkalinity will not help reduce pH rise. It will cause more pH rise. This is because at higher levels of carbonate alkalinity, there will be more carbonic acid which will outgas as carbon dioxide, which raises pH.

Adding about 20 to 30 ppm of cyanuric acid will help. This can be accomplished by using dichlor. After a cumulative use of about 3 ounces (weight) of dichlor or 30 ppm, your cyanuric acid should be about 27.

Dichlor is slightly acidic, so you would want the pH slightly higher than your target pH before adding dichlor so that the pH ends up exactly where you want it.

Adding 30 to 50 ppm of borates (From Borax or boric acid) will also help reduce pH rise.

You should maintain a Saturation Index of about -0.3 to 0.0. Adding cyanuric acid and borates will lower your CSI to below -0.3 at a pH of 7.6, so you would want to add some calcium to about 150.

I suggest that you keep the pH between 7.6 and 7.8. A higher pH helps reduce pH rise.

You guys are starting to contradict on the use of Borax (borates). I assume they are one in the same. I have used Borax to raise pH with little effect on TA. What other benefit is there?

This is (in stead of) using just backing soda to raise pH and TA.

Greg

[TomC]

I now understand that TA controls the amount of ph creep and was wondering if a TA of 60ppm would be enough to keep the ph in check.

Total alkalinity only measures how much acid it takes to lower the pH. It doesn't really tell you how much base it would take to raise the pH. Total acidity tells you how much base it takes to raise the pH. If you know the components of total alkalinity, you can estimate the total acidity based on the equilibrium equations.

The primary components of total alkalinity and total acidity will be:

Carbonic acid, bicarbonates and carbonates.

Boric acid and borates.

Cyanuric acid and cyanurates.

Phosphoric acid and phosphates (If using a phosphate buffer).

A higher carbonate alkalinity will not help reduce pH rise. It will cause more pH rise. This is because at higher levels of carbonate alkalinity, there will be more carbonic acid which will outgas as carbon dioxide, which raises pH.

Adding about 20 to 30 ppm of cyanuric acid will help. This can be accomplished by using dichlor. After a cumulative use of about 3 ounces (weight) of dichlor or 30 ppm, your cyanuric acid should be about 27.

Dichlor is slightly acidic, so you would want the pH slightly higher than your target pH before adding dichlor so that the pH ends up exactly where you want it.

Adding 30 to 50 ppm of borates (From Borax or boric acid) will also help reduce pH rise.

You should maintain a Saturation Index of about -0.3 to 0.0. Adding cyanuric acid and borates will lower your CSI to below -0.3 at a pH of 7.6, so you would want to add some calcium to about 150.

I suggest that you keep the pH between 7.6 and 7.8. A higher pH helps reduce pH rise.

You guys are starting to contradict on the use of Borax (borates). I assume they are one in the same. I have used Borax to raise pH with little effect on TA. What other benefit is there?

This is (in stead of) using just backing soda to raise pH and TA.

Greg

Hi Greg,

I came back to this thread with a borate question too. Well actually I have no idea what borate is. Is it a product, or a compound (like Javex vs bleach). Anyway, what is a borate and where do I find such a thing?

In one of the replies above, Nitro mentions getting his water balanced and then "setting" it with borax. From that I assume that borax is a final step thing. Is that your understanding too?

Thanks...Tom

[chem geek]

Borates are what we generically call what is really boric acid in water. You can most easily add them from a product such as Proteam Gentle Spa which is actually mostly boric acid. It is fairly pH neutral, but once added in a quantity to get 50 ppm Borates (technically, 50 ppm Boron), then it acts as a pH buffer, especially effective at slowing down the rate of pH rise. You would use this in conjunction with lowering the Total Alkalinity (TA), usually to around 50-70 ppm or wherever is necessary to have the pH be more stable (you usually lower the TA first since it's easier to do before you add the borates). In essence, you are substituting one pH buffer for another, but the carbonate buffer, which is mostly what TA measures, actually CAUSES a rise in pH if the TA is too high whereas the borates do not.

20 Mule Team Borax will increase borates, but by itself it is used to raise the pH -- it is not pH neutral (unlike boric acid which is close to pH neutral since it is such a weak acid at spa pH). So instead of using Gentle Spa, one can use a combination of 20 Mule Team Borax and acid added separately to achieve the same effect less expensively, but Gentle Spa isn't terribly expensive for the quantities used in a spa so most people use that instead. When 20 Mule Team Borax is added by itself in smaller quantities, it is a base used to raise the pH (and yes, it increases the borates level a little); when it is added in larger quantities along with acid, it is being used to increase the borates level in the spa.

Richard

[quantumchromodynamics]

Borax can be found in the laundry aisle of most supermarkets. The ingredient should be sodium tetraborate decahydrate

For a 400-gallon hot tub, you would add 6 fluid ounces of 31.45% muriatic acid followed by 12 ounces (weight) of Borax and then another 6 fluid ounces of muriatic acid and finally, 12 more ounces of Borax. Dilute chemicals in a clean bucket before adding them to the hot tub.

An easier method is adding 15 ounces (weight) boric acid. Richard noted Gentle spa as one source of boric acid. Here are other sources of boric acid.

http://www.aaa-chemicals.com/2potegrboac1.html

http://www.chemistrystore.com/product.cgi?...7201&group=

I would like to recognize WaterBear for his extensive and valuable contributions to the knowledge about using borates, and about water maintenance in general. Thanks, WaterBear.

[chem geek]

Here, here! Waterbear (Evan) first did the borates experiments in his own pool and described them here at The PoolForum in 2006. At the time, there were discrepancies with dosages calculated from BleachCalc and we figured out that borates were supposed to be measured in units of ppm Boron. The use of borates in SWG pools to reduce the rate of pH rise was a starting point, but we then figured out how lowering the TA also helped. These same principles also apply to spas, but to an even greater extreme in terms of how low the TA may need to go to get to pH stability.

[OttawaGreg]

I now understand that TA controls the amount of ph creep and was wondering if a TA of 60ppm would be enough to keep the ph in check.

Total alkalinity only measures how much acid it takes to lower the pH. It doesn't really tell you how much base it would take to raise the pH. Total acidity tells you how much base it takes to raise the pH. If you know the components of total alkalinity, you can estimate the total acidity based on the equilibrium equations.

The primary components of total alkalinity and total acidity will be:

Carbonic acid, bicarbonates and carbonates.

Boric acid and borates.

Cyanuric acid and cyanurates.

Phosphoric acid and phosphates (If using a phosphate buffer).

A higher carbonate alkalinity will not help reduce pH rise. It will cause more pH rise. This is because at higher levels of carbonate alkalinity, there will be more carbonic acid which will outgas as carbon dioxide, which raises pH.

Adding about 20 to 30 ppm of cyanuric acid will help. This can be accomplished by using dichlor. After a cumulative use of about 3 ounces (weight) of dichlor or 30 ppm, your cyanuric acid should be about 27.

Dichlor is slightly acidic, so you would want the pH slightly higher than your target pH before adding dichlor so that the pH ends up exactly where you want it.

Adding 30 to 50 ppm of borates (From Borax or boric acid) will also help reduce pH rise.

You should maintain a Saturation Index of about -0.3 to 0.0. Adding cyanuric acid and borates will lower your CSI to below -0.3 at a pH of 7.6, so you would want to add some calcium to about 150.

I suggest that you keep the pH between 7.6 and 7.8. A higher pH helps reduce pH rise.

You guys are starting to contradict on the use of Borax (borates). I assume they are one in the same. I have used Borax to raise pH with little effect on TA. What other benefit is there?

This is (in stead of) using just backing soda to raise pH and TA.

Greg

Hi Greg,

I came back to this thread with a borate question too. Well actually I have no idea what borate is. Is it a product, or a compound (like Javex vs bleach). Anyway, what is a borate and where do I find such a thing?

In one of the replies above, Nitro mentions getting his water balanced and then "setting" it with borax. From that I assume that borax is a final step thing. Is that your understanding too?

Thanks...Tom

Tom,

OK, so Borite and Borax are different things (somewhat), news to me. I have used Borax to raise the pH and add some borites without effecting the TA as much. BTW, we don't have 20 Mule team here in Canada but at (Home Hardware again) you can find it in a blue box simply labeled BORAX.

I have been pH high since my last refill so haven't had to use it. If I continue along with the Bleach method (13+ pH) then I don't ever expect to be adding any, unless I can understand this method of locking the ph down using Borites...

Greg

[chem geek]

20 Mule Team Borax or any other borax product will raise the pH when added to pool water and is better than pH Up in that it only raises the TA by about half as much.

Na₂B₄O₇•10H₂O ---> 4B(OH)₃ + 2Na⁺ + 2OH^- + 3H₂O

Borax ---> Boric Acid + Sodium Ion + Hydroxyl Ion + Water

So Borax becomes boric acid in water and the sodium and hydroxyl ions are like adding lye to the water which raises its pH.

Products like Proteam Gentle Spa are mostly boric acid so when added to water they don't change the pH very much.

Both Borax and Proteam Gentle Spa will increase the level of boric acid (what we've been calling "borates") in the water, but the Borax significantly raises the pH while the Gentle Spa does not.

[OttawaGreg]

20 Mule Team Borax or any other borax product will raise the pH when added to pool water and is better than pH Up in that it only raises the TA by about half as much.

Na₂B₄O₇•10H₂O ---> 4B(OH)₃ + 2Na⁺ + 2OH^- + 3H₂O

Borax ---> Boric Acid + Sodium Ion + Hydroxyl Ion + Water

So Borax becomes boric acid in water and the sodium and hydroxyl ions are like adding lye to the water which raises its pH.

Products like Proteam Gentle Spa are mostly boric acid so when added to water they don't change the pH very much.

Both Borax and Proteam Gentle Spa will increase the level of boric acid (what we've been calling "borates") in the water, but the Borax significantly raises the pH while the Gentle Spa does not.

Thanks Chem Geek for that explanation on Borax & Borates.

The only reason I used Borax was when my problem was low pH & high TA.

My water comes out the tap 7.5pH and will only drift UP now as I use bleach. So there is no reason I can see to add Borax to my tub in the foreseeable future. The question is am I missing something (I mean is the water missing something) by not adding Borates?

thanks,

Greg

[chem geek]

Greg,

What you are missing by not having 50 ppm Borates in the water is the additional pH buffering that it provides. When one is using bleach (or any other hypochlorite source of chlorine such as lithium hypochlorite), then one must keep the TA low in order to prevent the pH from rising from carbon dioxide outgassing. However, a lower TA provides less pH buffering so every time you add the bleach the pH will rise and then as the chlorine gets used up it will fall again. Having borates in the water buffers the pH so this swing in pH is cut down significantly.

There are other more subtle benefits to the borates. They are a mild algaecide so in pools this often results in somewhat lower chlorine demand if nascent algae growth is an issue. In both pools and spas, the borates add a sparkle to the water, possibly by reducing the surface tension of the water (the meniscus when taking measurements seems flatter when there are borates in the water). I added 50 ppm Borates to my pool at the beginning of this year and am very happy with the results -- in my case, it takes the edge off of algae growth if/when I ever forget to add chlorine and let it get too low (rarely happens, but I did screw up once upon spring opening as described here).

For normal amounts of bleach added to a spa, the pH buffering effect isn't that important. For example, with a pH of 7.7, TA of 50, CYA of 30, then adding 5 fluid ounces of 6% bleach in 350 gallons (say, for one person-hour of soaking) would raise the pH to 7.93. If one had 50 ppm Borates in the water, the pH would rise to 7.74. If you shock with a lot more bleach, then the extra pH buffering may be more important. Also, if the pH is still rising over time even after chlorine consumption/usage lowers the pH in the short-run, then the Borates reduce the frequency of acid addition though they don't reduce the total amount of acid that needs to be added (at least not in theory).

Richard

[quantumchromodynamics]

You guys are starting to contradict on the use of Borax (borates). I assume they are one in the same. I have used Borax to raise pH with little effect on TA. What other benefit is there?

I know that it can seem contradictory when we say add borates to raise pH and then we say add borates to reduce pH rise. Let me see if I can add to what others have said using the weak acid theory, which is not exactly accurate for boric acid. (See below).

pH is a measure of the active hydrogen ions in the water. Its counterpart is pOH, which measures the concentration of hydroxyl ions in the water. The pH + pOH always add up to 14.

When a weak acid like carbonic acid (H₂CO₃) or cyanuric acid (C₃H₃N₃O₃) is added to the water, it partially deprotonates ( Some of the hydrogen ions (protons) dissociate (disconnect) from the acid) based on the pH and the pKa of the acid.

Therefore, when carbonic acid is added to water, some of the hydrogen ions dissociate from the acid to form a base called the bicarbonate ion HCO₃^-or the carbonate ion CO₃^2-.

The formula is 10^X/ (1 + 10^X) = Percent of the acid base pair that is acid. X = pKa - pH.

Here are some values for boric acid.

pH = 8.3 Boric acid = 91 % Borate ion = 9 %.

pH = 8.2 Boric acid = 93 % Borate ion = 7 %.

pH = 8.1 Boric acid = 94 % Borate ion = 6 %.

pH = 8.0 Boric acid = 95 % Borate ion = 5 %.

pH = 7.9 Boric acid = 96 % Borate ion = 4 %.

pH = 7.8 Boric acid = 97 % Borate ion = 3 %.

pH = 7.7 Boric acid = 97.5 % Borate ion = 2.5 %.

pH = 7.6 Boric acid = 98 % Borate ion = 2 %.

pH = 7.5 Boric acid = 98.4 % Borate ion = 1.6 %.

Boric acid works in a similar way to cyanuric acid and carbonic acid except that it associates or dissociates the hydroxyl ion instead of the hydrogen ion.

When Borax is added to the water, the borates release hydroxyl ions, which connect to free active hydrogen ions, which raises the pH. Therefore, at a pH of 7.5, 98.4 % of the borates will become boric acid by releasing hydroxyl ions. This also decreases the concentration of hydrogen ions and raises the pH.

Boric acid acts as an acceptor of hydroxyl ions as the pH increases. For example, if the pH goes from 7.6 to 8.0, the amount of boric acid is decreased from 98 % to 95 % and the amount of borate ion goes from 2 % to 5 %, because the boric acid connects with hydroxyl ions to form B(OH)₄⁻ (tetrahydroxyborate anion) as the pH increases.

The boric acid removes the hydroxyl ion from the water to leave the hydrogen ion. This lowers the pH.

B(OH)₃ + 2 H₂O <> B(OH)₄⁻ + H⁺ + H₂O

Another way to look at it is that boric acid resists pH rise by connecting with OH^- (The hydroxyl ion).

B(OH)₃ + OH^- <> B(OH)₄⁻

Borax contains Na₂[b₄O₅(OH)₄]•8H₂O, which becomes

4B(OH)₃ + 2Na + 2OH^- + 3 H₂O

(As Richard has previously shown.)

I hope that this has helped rather than caused more confusion.

[styro]

You guys are starting to contradict on the use of Borax (borates). I assume they are one in the same. I have used Borax to raise pH with little effect on TA. What other benefit is there?

I know that it can seem contradictory when we say add borates to raise pH and then we say add borates to reduce pH rise. Let me see if I can add to what others have said using the weak acid theory, which is not exactly accurate for boric acid. (See below).

pH is a measure of the active hydrogen ions in the water. Its counterpart is pOH, which measures the concentration of hydroxyl ions in the water. The pH + pOH always add up to 14.

When a weak acid like carbonic acid (H₂CO₃) or cyanuric acid (C₃H₃N₃O₃) is added to the water, it partially deprotonates ( Some of the hydrogen ions (protons) dissociate (disconnect) from the acid) based on the pH and the pKa of the acid.

Therefore, when carbonic acid is added to water, some of the hydrogen ions dissociate from the acid to form a base called the bicarbonate ion HCO₃^-or the carbonate ion CO₃^2-.

The formula is 10^X/ (1 + 10^X) = Percent of the acid base pair that is acid. X = pKa - pH.

Here are some values for boric acid.

pH = 8.3 Boric acid = 91 % Borate ion = 9 %.

pH = 8.2 Boric acid = 93 % Borate ion = 7 %.

pH = 8.1 Boric acid = 94 % Borate ion = 6 %.

pH = 8.0 Boric acid = 95 % Borate ion = 5 %.

pH = 7.9 Boric acid = 96 % Borate ion = 4 %.

pH = 7.8 Boric acid = 97 % Borate ion = 3 %.

pH = 7.7 Boric acid = 97.5 % Borate ion = 2.5 %.

pH = 7.6 Boric acid = 98 % Borate ion = 2 %.

pH = 7.5 Boric acid = 98.4 % Borate ion = 1.6 %.

Boric acid works in a similar way to cyanuric acid and carbonic acid except that it associates or dissociates the hydroxyl ion instead of the hydrogen ion.

When Borax is added to the water, the borates release hydroxyl ions, which connect to free active hydrogen ions, which raises the pH. Therefore, at a pH of 7.5, 98.4 % of the borates will become boric acid by releasing hydroxyl ions. This also decreases the concentration of hydrogen ions and raises the pH.

Boric acid acts as an acceptor of hydroxyl ions as the pH increases. For example, if the pH goes from 7.6 to 8.0, the amount of boric acid is decreased from 98 % to 95 % and the amount of borate ion goes from 2 % to 5 %, because the boric acid connects with hydroxyl ions to form B(OH)₄⁻ (tetrahydroxyborate anion) as the pH increases.

The boric acid removes the hydroxyl ion from the water to leave the hydrogen ion. This lowers the pH.

B(OH)₃ + 2 H₂O <> B(OH)₄⁻ + H⁺ + H₂O

Another way to look at it is that boric acid resists pH rise by connecting with OH^- (The hydroxyl ion).

B(OH)₃ + OH^- <> B(OH)₄⁻

Borax contains Na₂[b₄O₅(OH)₄]•8H₂O, which becomes

4B(OH)₃ + 2Na + 2OH^- + 3 H₂O

(As Richard has previously shown.)

I hope that this has helped rather than caused more confusion.

I was hoping to get some info from my Canadians forum readers who know the product name to replace the famous product BORATES which is not available in Canada.

Thanks

[chem geek]

The easiest sources of boric acid are the spa products Proteam Gentle Spa, Rendezvous pH Magic or Leisure Time pH Balance Plus. These are all Boric Acid so can be used to add 50 ppm Borates where you can use The Pool Calculator to calculate dosing. 13.4 ounces weight, or around 15 ounces volume (almost 2 cups) of these products in 350 gallons would yield 50 ppm Borates.

As for 20 Mule Team Borax which can also be used to raise pH, it is available at the stores listed here. If your local Wal-Mart doesn't carry it, ask them if they can get it or where you can get it or if there is another local brand of Borax.

[OttawaGreg]

I hope that this has helped rather than caused more confusion.

I was hoping to get some info from my Canadians forum readers who know the product name to replace the famous product BORATES which is not available in Canada.

Thanks

The box I got was from Home Hardware. It's Natura brand and comes in a blue box simply labeled BORAX. Natural cleaner and deodorizer. Detergent booster & Stain remover. They do not list the ingredients or the active ingredient. It simply states it contains NO phosphates or chlorine.

Hope this helps,

Greg from Canada (Ottawa)

BTW I have not added any BORAX to my new tub in fear of disturbing the balance I now have had for three weeks of following the Dychlor/Bleach method. My tub smells like you've jumped in a fresh laundry basket.. I love it!!!!!

I'm adding about 200ml of Clorox 6% bleach after each use. That appears to be what we need to keep a residual CL of about 1-2. I'm topping up with some MPS (1tbsp) every few days. The pH just sticks around 7.5-7.8. The water is crystal clear.