How a Borate/Bicarbonate Buffering System Works - Rudy (sitting in for Wayne)

Rudy (00:00.534)
Hey guys, welcome to Thursdays with Wayne. With one twist, I'm not Wayne. This is Rudy stepping in for the big guy. Normally Thursdays is about water testing. So I want to try to stick with that same motif. What I want to cover, what I'd like to cover is how buffers work. Buffers, your bicarbonate buffering system and your borate buffering system. That's what I want to dive into.

It's been a big question. A lot of folks are always curious. Does it work? The answer is yes. But keep in mind the main reason we look at these things, the main reasons we use borates, the main reasons that we keep our total alkalinity in balance are to aid in preventing a pH drift either upward or downward. So imagine you had a fort. That is fort pH. And you want to protect it. So you send out troops and you establish a front line.

Let's say there's something coming that risks lowering your pH. This is where we build up our frontline of bicarbonate troops. As those things come through, the bicarbonate troops takes out as many of them as it possibly can. And the way it does this is by changing it into something that won't lower the pH. But the bicarbonate uses itself up in the process.

So yeah, you'll take out a lot of enemy soldiers, but you're also going to lose some of your own. You have to be ready for that. So that's the reason why when you add muriatic acid, the pH will come down. But depending on where your total alkalinity is, that determines how far it'll drop. The same with a heavy rain. Rainwater is acidic. Rainwater is always acidic, not acid rain, just acidic. Acid rain is super, super acidic. So.

As that rain comes through, you have your front line out there getting ready to handle everything that will lower the pH. By changing it into something that is not acidic and using some of itself up in the process. Unfortunately, some of it does still get through and attack fort pH. And that does bring the level down slightly, but not as much as if we did not have a well fortified front line. So the more troops we have on that front line,

Rudy (02:25.526)
the more we can prevent the evil pH lower to get through. Borates is very much the same. Maybe something's attacking our fort that wants to raise the pH. This is where your borate buffering system comes in handy. The borates change whatever that is into something else by adopting it and changing the borate into something else. So the borate's still there.

it just becomes something else. But the same principle, we have that front line and the stronger we build that front line, the more protection we have against whatever's coming in to try to lower or increase the pH. That's the main reason that we use buffering systems. That's the main reason we use buffering systems in swimming pools. Again, to prevent pH drift upward or downward. We don't want either one. There are some other benefits.

That's one of the reasons this became extremely popular in the post pandemic years, borates, because borates will not only keep the pH from drifting upward, it does also serve as an algaestat. An algaestat prevents algae. It won't kill algae, but it will prevent it from becoming established. It prevents it from gaining a foothold, which is fantastic because if the borates handling

the algae, that means the chlorine we put into the water doesn't have to mess with that. It frees itself up to sanitize and disinfect other things, which also means that our chlorine supply should last longer because we don't need as much of it now to keep up with the problems that we have because we have the borates helping us out by keeping the algae away. The other thing borates do is it does act as a bit of a scale preventative.

It does ensure you get that crisp, clear Caribbean look to the water that we want. Also a nice silky feel to it. And it does also on top of that help to prevent UV degradation of chlorine. So it acts kind of like cyanuric acid, just not as good as cyanuric acid. Speaking of which, cyanuric acid does also buffer your pH.

Rudy (04:50.87)
works best from preventing, works best in preventing a downward drift. So we have that. So by maintaining a solid, a good total alkalinity, cyanuric acid level and borate level, you can, and I don't want to use the word lock in place because it's not exactly accurate, but you can make it more challenging for your pH to fluctuate.

So as the pH, as things come in that would lower the pH, we got that front line out there, it deadens the impact of whatever that is on the pH. So the pH will not drop as much as if your total alkalinity or your cyanuric acid was lower. Again, total alkalinity, much, much more buffering capacity than cyanuric acid, but cyanuric acid is there, so I have to include it. I do also have to fairly say,

that a borate level will also help slightly in preventing a downward drift, just as total alkalinity will work slightly in preventing an upward drift. So we have both of those at hand.

If something was coming to attack our pH, that was going to increase the pH, again, that front line that we built up, the stronger the front line, the less of those enemy troops are gonna get through.

Rudy (06:21.174)
So that's it. A buffer is a chemical that serves as the water's ability to resist a change in pH. And again, it does this by changing things that would lower the pH or increase the pH into something that won't. Total alkalinity, again, the one that you're probably most familiar with, your bicarbonate buffer system.

even though it buffers against both an upward and downward drift, it does do its best job in resisting a pH drop. 1 .4 pounds of sodium bicarbonate, that's the amount that we add to increase the total alkalinity of 10 ,000 gallons of water by 10 parts per million. Maintaining a cyanuric acid level, as I mentioned before, will do the same, just not as good as total alkalinity does.

It will keep the pH from going up or down and does its best job against preventing a dip. Like I said, initially, it won't stop the pH level from moving, but it does make it much more difficult for it to go from point A to point, another point on that zero to 14 scale. Now, 13 ounces of cyanuric acid, that will increase the cyanuric acid level of 10 ,000 gallons of water by 10 parts per million. Establishing the borate level that we talked about,

will also buffer against a movement in either direction but excels in resisting an upward drift. Borate and water work similarly to the total alkalinity in that it changes things that would drive the pH upward into something that won't. Obviously if the goal is to use much less acid, this is the level that is most important. But it's the combination of the three that really keeps the pH in the acceptable range.

Rudy (08:16.374)
So when looking at BOR8, the BOR8 symbol, it's H3, B03.

Rudy (08:25.814)
We have other things in the water.

Rudy (08:31.67)
Borate acts as a buffer against, again, an upward drift in pH by stripping a hydroxide from a strong base like sodium hydroxide.

Rudy (08:50.134)
The sodium hydroxide then dissociates into sodium, which we're familiar with, which is a weak base. And then also...

into tetrahydroxyborate.

So it stays a borate product. It just strips that hydroxide ion away, dissociates sodium hydroxide into both sodium and then tetra borate hydroxide. Now, the dose. These are big pounds, big doses associated with borax or borates. So you can use borax right off the shelf at the supermarket. 37 pounds will raise your borate level.

of 10 ,000 gallons by 50 parts per million. The better way to go would be with boric acid, 23 .75 pounds will raise the borate level of 10 ,000 gallons of water by 50 parts per million. Why 50 parts per million? That's our max level. So assuming we're at zero, if you're using borax, 37 pounds. If you're using boric acid, 23 .75 pounds.

Now, the 20 mule team Borax is probably a lot easier to find. It's located in the laundry aisle of your local grocery store. But again, it does take a much, much higher dose and it will also jack up your pH and total alkalinity significantly requiring a large dose of acid to rebalance it. However, once it's rebalanced, it'll stay pretty much in place. Again, strong front line.

Rudy (10:28.842)
Another cool thing about borates, again, once it's established, it does not dissipate or degrade. It stays there. So the only way we lose borate in a pool after we establish a level is excessive backwashing.

Be either splash out, be either drag out, or if the pool has a leak, similar to calcium hardness, total dissolved solids, and cyanuric acid. Those things are all in there. Those things are all only going to increase with the exceptions noticed, or the exceptions noted, like draining.

Draining will definitely lower the level of any of those. You may find that you have to tweak it slightly over time, again, due to water loss from back washing, bath or drag out or splash out. Of course, a leak, with a leak, you will have difficulty maintaining a sufficient borate level, which brings up a great point. If you're gonna start using borates in a pool, you're also going to need a borate test kit. So make sure you have one of those. The best possible,

borate bicarbonate combo, the buffer system for your pool that you could set up would have a buffering, would have the level set as follows. Total alkalinity, 80 to 100 parts. The best possible borate bicarbonate buffer system would have levels at, the best possible borate bicarbonate buffer system would have a total alkalinity of 80 to 100 parts per million, a cyanuric acid level of 30 to 50 parts per million.

and a borate level of 30 to 50 parts per million.

Rudy (12:11.318)
no higher than 50 parts per million on the Boer VIII.

Rudy (12:46.718)
Boar rates may very well be the new craze in the swimming pool industry post pandemic. It's as close to being the magic pill as anything has ever come before. It's not new. This is a rebirth. This is an ancient pool pro secret that's making its way back because the pool industry hit hard times with the chlorine shortage. The team at PoolClor...

had conducted a lot of the original research using a borate buffering system in swimming pools back in the early 70s or early 80s. In the past couple of decades, Trouble Free Pool has also increased awareness of the many benefits of boron -oxygen compounds.

Rudy (13:30.708)
Again, to reiterate, what does borate do for you? It improves swimmer comfort, softens water, provides good algae control, reduces scaling, improves clarity, reduces corrosion, saves energy. It can be added easily and dissolves instantly. It improves oxidizer performance and longevity, especially with chlorine.

And it gives you that amazing buffering capacity. And again, buffering is the main reason we had always used borates in swimming pools. The fact that it's an algaestat, we're focusing on that now because we have those benefits with chlorine supply. Well, Christ, with chlorine supply, well, in shortage, remember we called it a poolmageddon. And now the price is through the roof.

So that VOR8 buffering system still does help stretch your supply.

Rudy (14:32.438)
The way this works, the way any buffering system works, is we establish a level of a weak acid, like carbonic acid or boric acid, and then its conjugate base, like bicarbonate or tetraborate. This solution in water can neutralize strong acids or bases by turning them into something else. The buffer makes that happen by donating or accepting a proton, a hydrogen ion.

when the pH level is threatened with a downward drift.

Rudy (15:07.062)
We say that total alkalinity is the water's ability to resist change in pH. Total alkalinity can do this because bicarbonate along with carbonic acid is a bicarbonate buffering system. You have a weak acid, you have a weak base. This buffering system, again, buffers against the pH moving up or down, but does its best job in preventing a downward drift. So if we already have a total alkalinity level in a good place between 80 and 100,

Do we still need to establish a borate level? Yes. Do you need to? No. Is it beneficial? Absolutely.

Rudy (15:49.258)
Even with a bicarbonate buffering system, a borate buffering system will still work to help prevent a change in pH. It also tends to specialize in preventing an upward drift. It's better at preventing an upward drift than that bicarbonate system.

Rudy (16:12.086)
And that all comes down on both to something known as a pKa value. pKa value, pKa is what we would call the perfect pH. That's the pH, I'm not talking about between 7 .2 and 7 .8, I'm talking about the perfect pH for a bicarbonate buffering system. The perfect pH for a borate buffering system. That's the point where we have just as much of the weak acid as we do,

the conjugate base. So for example, with borate, that pH level happens to be 9 .1. That's where we have equal amounts of conjugate base and the weak acid.

Rudy (17:03.03)
So understand this is also an up one downward scenario.

If the pKa, the perfect pH, is 9 .1 for borates, that means that it is a very effective buffer from a pH of 8 .1 through 10 .1. So as your pH increases toward 8 .1, it gets harder and harder and harder for the pH to drift upwards. So that works well because we have our acceptable range of 7, 2 to 7, 8.

We have the borates in there, 8 .1 to 10 .1. So it does tend to keep it in that acceptable range. On the opposite side, well, so, and again, the perfect amount of the conjugate and the weak acid with borate is boric acid. The weak base, the conjugate base is tetraborate. These are words that I'm sure you've heard before. A pKa value is the perfect pH.

not your ideal pH range, but the pH at which a specific busfuring system works best. Some refer to pKa value as the means to measure the strength of an acid, which it is, but that's a whole different conversation. So when we add that weak acid to pool water, an amount of conjugate base, which is also weak, forms. For example, many large commercial facilities use CO2, carbon dioxide, for pH control.

This works because upon injection, the CO2 becomes carbonic acid, the weak acid. We are also aware that this is the only means of lowering pH that will increase the total alkalinity. That's because that carbonic acid donates a hydrogen ion, becoming bicarbonate ions. So we have HC.

Rudy (18:58.39)
H2CO3, which is carbonic acid, that donates a hydrogen ion. The hydrogen ion does lower the pH because the pH is the measurement of hydrogen ion activity, which leaves us with HCO3, which is bicarbonate. That's our conjugate base. So there we have the CO2 forming carbonic acid, donating a hydrogen ion, lowering the pH.

forming HCO3, which is bicarbonate, increasing the total alkalinity, which is exactly what happens when...

Rudy (19:35.126)
we add CO2 to the water. Now let's say muriatic acid is added, where we have established a bicarb buffer. Let's say we add muriatic acid and we have our bicarbonate buffer system. The bicarbonate ion base, HCO3, accepts a proton and becomes carbonic acid, which is H2CO3, which is...

Rudy (20:11.158)
which is just simply bicarbonate HCO3 with the addition of one hydrogen from the muriatic acid becoming that H2CO3, which is our carbonic acid. The HCl, the muriatic acid then loses the hydrogen ion. Muriatic acid is HCl, which becomes chloride, which is simply, which becomes chloride. By changing the acid to something else, the effect of the dose of the acid on the pH is changed.

So we changed CO2 into carbonic acid. Carbonic acid donates a hydrogen ion, which lowers the pH. We're left with CO3. We're left with HCO3, which raises the total alkalinity because that's bicarb. And then the HCl, the hydrochloric acid that we added, becomes chloride.

The pKa value for a specific buffering system, again, is where we have just as much of the weak acid as we do of the conjugate base, a one -to -one ratio. So for example, with the bicarbonate buffering system this time, that pKa value is 6 .1. So again, with our give one, take one, up one, down one, we have 7 .1.

5 .1, 5 .1 to 7 .1 is where we get our best buffering capacity from that bicarbonate system. So now if you look at where our acceptable range is on the scale, as the pH tries to move downward, it becomes increasingly harder because of the bicarb buffer system. As the pH moves upward, it becomes increasingly difficult due to the borate buffering system. So with this ratio, we have a pH of 6 .1.

That means we have just as much of our weak acid as we do of our conjugate base, which is where we have our greatest buffering capacity. With our borate system in place, we should add a dose, if with our borate system in place, if we added a dose of sodium hydroxide, which is caustic soda, the boric acid would neutralize that dose, but not by giving a proton. In fact, boric acid is not very giving at all.

Rudy (22:22.198)
It's more of a take -take type of thing, and it's not even a measly old proton. It wants more. Boric acid neutralizes a strong base like sodium hydroxide by taking the hydroxide away, turning itself into tetrahydroxy borate, and by changing the acid into something else, by changing the acid to something else, the dose of the acid's effect on pH has changed.

by changing the base and itself into something else, the dose of a strong base on the water's pH is changed. Borate buffering system works exactly the same as a bicarbonate buffering system, except totally different. How about that one? Boric acid does not donate a hydrogen ion. We discussed that, as we've seen with carbonic acid. Instead, boric acid takes a hydroxyl ion from the water.

to form its conjugate base, which is tetrahydroxy borate. We also see here the possibility of several other borate species existing within those same ranges as a conjugate base. This is because boric acid breaks the buffering system rules instead of giving it and by not donating a proton. Without.

Borax again, we can use Borax as disodium tetraborate decahydrate. It can be used if it's activated by an acid such as hydrochloric acid, which then creates that Borax HCl, that Borax muriatic acid buffer system, which is great because when you add boric acid, it's gonna skyrocket your pH and total alkalinity. So you're gonna need to add a large dose of acid anyway. Regardless,

With the borate buffer system, 9 .1 again is the perfect pH and that's the point where we have just as much of the acid as we do, the weak acid as we do the conjugate base. 9 .1 equal amounts of boric acid and tetrahydroxy borate or whatever conjugate base was actually formed because again, like we stated, we can get other borate species and where our borate buffering system buffers best is again in preventing an upward drift.

Rudy (24:36.694)
I mean, that's the cool thing about it is you do get a little bit of leeway here. In both scenarios, we're looking at an up one down one situation as far as where the best buffering capacity is. So the low end of that borate system and the high end of that bicarbonate system happens to book end our acceptable range pretty darn well.

So that's why they say lock it in place. It doesn't really lock it. It doesn't stop it from moving. But it does make it more challenging for the pH to move in either direction because we have that well -established front line that's protecting for pH. The closer the pH gets to the pKa value, the greater the level of resistance the pH will meet. With a borate buffer system in place, the closer the pH comes to a pH level of 8 .1,

the amount of base to make an upward change increases exponentially. It would be the same if we recognize the downward drift with the total alkalinity. As the pH gets closer to 7 .1, the more resistance against change it will face. I hope this isn't all too confusing.

That's all I have for you on Thursday. I hope that I kept it within the chemical testing guidelines of what you normally get from Wayne. So I will say, I'm gonna see you guys again on Friday, but until then, be good, be safe.