Experimental testing of Brightwell Boost pH +

[Randy Holmes-Farley]

The fact that the expected alk boost from a 0.1 pH unit rise using hydroxide is going to be hard to reliably detect is why I wanted to push the addition at least as high as the directions permit, and is also why I want to test hydroxide doing the same pH boost.

 

[Miami Reef]

Aeration will drive the pH boost far lower, and if alk actually isn’t raised, will drive it to none.

How does that make sense? Why would aeration lower alkalinity? From precipitation? Aeration can lower pH, but not alk, as far as I know. Am I missing something?

 

[Randy Holmes-Farley]

How does that make sense? Why would aeration lower alkalinity? From precipitation? Aeration can lower pH, but not alk, as far as I know. Am I missing something?

I perhaps wrote that unclearly.

Aeration will drive the pH boost far lower, and if alk actually isn’t raised, will drive the pH boost to none.

Here's what I observed when adding various additives:

Chemistry And The Aquarium: The Relationship Between Alkalinity And pH

Randy answers many questions in this complex relationship.

reefs.com

Alkalinity Supplements​

One of the most common issues that reefkeepers face involves supplementing alkalinity while maintaining a reasonable pH. Alkalinity supplements impact pH in a variety of ways. One of these ways is the immediate altering of the pH. Different alkalinity supplements have different immediate impacts on pH, as most reefkeepers are aware. This impact is why, for example, limewater needs to be added slowly to a tank but sodium bicarbonate does not.

For this discussion, let’s presume that we want to supplement the carbonate alkalinity of a reef tank. That is, in the end we want to increase the bicarbonate and carbonate levels in the tank. There are a variety of ways to achieve this end, and these different ways have different immediate impacts on pH. Three of these ways (and combinations thereof) are fairly common in reefkeeping. These ways are addition of bicarbonate, carbonate, and hydroxide. In a reef tank that is permitted to equilibrate its total CO2 levels with the atmosphere, these additions all end up with the same final pH. That is, it is only the amount of alkalinity added that determines the final pH, not the nature of the additive itself.

In the short term, however, the impact on pH is very different. To quantify this, I measured to pH change on adding 0.5 meq/L of each of these alkalinity supplements to freshly made salt water (Instant Ocean made to S=35; alkalinity measured to be 2.26 meq/L by titration). Here’s the result for the pH found immediately, and then after 24 and 120 hours of sitting, unstirred, in an open 500- mL beaker:

Supplement	Initial pH	24 hour pH	120 hour pH
none	8.10	8.11	8.21
0.5 meq/L HCO3-	8.06	8.15	8.33
0.5 meq/L CO3–	8.44	8.28	8.34
0.5 meq/L OH-	8.76	8.47	8.33
0.5 meq/L H+	6.91	7.91	8.15

From this data it is clear to see the large increase in pH caused by the addition of hydroxide, and also the significant increase when using carbonate. Bicarbonate, on the other hand, shows the expected slight decrease in pH, but not nearly as much as is found with a strong acid of equal concentration. It is also clear that after sufficient time to equilibrate with atmospheric CO2, these differences disappear, and the pH is the same for all of the 0.5-meq/L alkalinity additions. This is an important result: in seawater in equilibrium with the atmosphere, for a given alkalinity there is a single pH that results, regardless of what was added to get to that alkalinity.

Here’s how to think of these additions. When these chemicals are added to the water, there is a change in the relative concentrations of carbonate and bicarbonate, and it is the ratio of these two ions that determines the pH.

 

[Randy Holmes-Farley]

The article goes on to detail chemically what happens in seawater when each of these alk additive chemicals is added, for anyone interested. The hydroxide addition, in particular, relates to this thread:

Hydroxide Addition
For hydroxide addition, the first thing that happens is that bicarbonate is converted into carbonate:

9. HCO3– + OH– → CO3—

and the small amount of carbonic acid present is converted into bicarbonate:

10. H2CO3 + OH– → HCO3– + H2O

The net effect is that the pH rise that is normally encountered by adding hydroxide to water is reduced. For example, adding 0.5 meq/L of hydroxide to freshwater would drive the pH into the 10’s. In seawater, the pH rises much less, and the conversion of bicarbonate to carbonate is largely responsible.

In this situation, the tank is now deficient in H2CO3 (because the small equilibrium amount of H2CO3 normally present was partially converted to bicarbonate by the OH– addition), and the tank proceeds to absorb CO2 from the air, bringing the pH back down a bit by releasing H+. There are many ways to show these reactions, but the net process involves CO2 from the air becoming carbonic acid, the carbonic acid deprotonating to bicarbonate, and some of the bicarbonate deprotonating to carbonate:

11. CO2 (atmosphere) + H2O → H2CO3

12. H2CO3 → HCO3– + H+

13. HCO3– → CO3— + H+

The reactions taking place in equations 11-13 all serve to lower the pH (from 8.76 to 8.33 in the experiment above). When equilibrium is reached, however, the pH has not dropped all of the way back to the point before the hydroxide was added, but is slightly elevated (8.33 in the example above). When all is said and done, and the tank has fully equilibrated with the air, the hydroxide addition has caused the tank to experience an increase in bicarbonate and carbonate, and in pH.

 

[areefer01]

Do you think it might make sense to mandate the use of certain tests and also a time of when to measure alkalinity pre and post adding Boost pH?

What about every other test that is posted on this forum or others. Unless this is a certified lab most hobbyist will pay for over the counter kits and used different brands.

On the other hand I would expect product developers to have higher quality stuff or if using what hobbyist use then several different manufacturers to trend.

 

[MnFish1]

What kit would you recommend for this experiment?

Would running this experiment longer term (a few days) be a better idea? We can aerate the solution and maintain pH with Brightwell boost pH+. Won’t it be easier to see the effects on alkalinity when maintaining a pH of 8.3?

seems like one would need a probe of some kind like the Neptune (I've forgotten the name - since I dont believe in it)
However my guess is - (I have no connection to Brightwell, etc) - they are going to say any alkalinity changes are insignificant for a tank. Whereas @Randy Holmes-Farley is stating a different question. Both sides - IMHO - have merits. IMHO - the company should say our product does not significantly increase alkalinity in a reef tank - as compared to 'it doesn't'. I have not read their literature so I'm just giving my opinion

 

[MnFish1]

The fact that the expected alk boost from a 0.1 pH unit rise using hydroxide is going to be hard to reliably detect is why I wanted to push the addition at least as high as the directions permit, and is also why I want to test hydroxide doing the same pH boost.

Right - I think this commentary from the company MAY be a way to skirt actual science. I dont know However - a change of alkalinity +- 0.3 - to me means the company's correct - its 'clinically insignificant'.

 

[Miami Reef]

Aeration will drive the pH boost far lower, and if alk actually isn’t raised, will drive the pH boost to none.

That’s the point. We can’t go over 8.3 pH in this experiment because Brightwell will say we didn’t follow the directions properly. By reducing the pH in the test vial with aeration, like what would happen in a reef tank, we can continue adding more of the brightwell solutions to maintain the pH.

Thus, if the hydroxide DOES increase alk, we can much clearly see the rise if we dosed to maintain 8.3pH after a few days.

 

[Randy Holmes-Farley]

Right - I think this commentary from the company MAY be a way to skirt actual science. I dont know However - a change of alkalinity +- 0.3 - to me means the company's correct - its 'clinically insignificant

If I said the same about kalkwasser : boosts pH and not alk if you add a small amount. You think that is ok? Really?


Jack has made it clear multiple times to me that the lack of effect on alk that he is referring to is not what is expected of hydroxide. He does not agree with Seachem's comments that pertain to their hydroxide only product. He says he knows hydroxide adds alk, and sells other products that claim to boost alk by supplying hydroxide. Obviously. Hydroxide in kalkwasser is a perfectly valid alk additive method as we all know . So is my two part using hydroxide.

I will say this: if the effect is the same as hydroxide, there's a serous problem (IMO).

If the effect is substantially lower than hydroxide to get the same pH boost, then perhaps we can argue about what is and is not significant, but at that point I'm really excited about a possible ground breaking technology to boost pH and not alk.

 

[Miami Reef]

Right - I think this commentary from the company MAY be a way to skirt actual science. I dont know However - a change of alkalinity +- 0.3 - to me means the company's correct - its 'clinically insignificant'.

But that’s with one dose. What happens if dosing overtime? We don’t only want to have a pH of 8.3 for one day. We want to maintain it daily.

An unexpected and unaccounted rise of 0.3dKH per day is substantial.

 

[Randy Holmes-Farley]

That’s the point. We can’t go over 8.3 pH in this experiment because Brightwell will say we didn’t follow the directions properly. By reducing the pH in the test vial with aeration, like what would happen in a reef tank, we can continue adding more of the brightwell solutions to maintain the pH.

Thus, if the hydroxide DOES increase alk, we can much clearly see the rise if we dosed to maintain 8.3pH after a few days.

I do not believe we need to have the same starting and finishing pH as his experiment. That's tricky. Just as long as the pH is in the range that he says for product application, and does not go above 8.5, then I think it's a fine experiment:

test requirements based on product claims:

7.5 - 10.0. dKH (2.7 - 3.6 meq/L)
do not exceed a pH value of 8.5
2.0 ml of Boost pH+ will raise the pH of 10 US gallons by about .1 to .3 pH,
Do not add more than 10 ml per 10 gallons per day!

 

[Randy Holmes-Farley]

But that’s with one dose. What happens if dosing overtime? We don’t only want to have a pH of 8.3 for one day. We want to maintain it daily.

An unexpected and unaccounted rise of 0.3dKH per day is substantial.

Of course.

 

[Randy Holmes-Farley]

That’s the point. We can’t go over 8.3 pH in this experiment because Brightwell will say we didn’t follow the directions properly. By reducing the pH in the test vial with aeration, like what would happen in a reef tank, we can continue adding more of the brightwell solutions to maintain the pH.

Thus, if the hydroxide DOES increase alk, we can much clearly see the rise if we dosed to maintain 8.3pH after a few days.

OK, I see what you are saying. Clever. Repeat the procedure several times on the same tank water, stirring a bit between times, if needed to keep the pH below the stated max (8.5), and see what the alk effect is since it may be much easier to detect properly.

I think that's good. I'd measure after each dose anyway, however.

The directions say the max dose per day is 1 mL per gallon. I cannot see how its an issue to speed up that process for testing (Jack did in his testing).

 

[taricha]

From Jack:

We did a little test this morning to see what would happen in a test such as this.

1) We took 1 gallon of tank water from an established aquarium, the pH of the sample was tested with a freshly calibrated probe and was 8.03. The alkalinity was tested via API test kit and was 9.0

2) We added 1ml of Boost pH+ from a lot numbered bottle of shelf stock, stirred and retested 5 minutes after adding. The results were pH at 8.19 and alkalinity was 9.0

3) We added another 1ml of Boost pH+ from the same bottle, stirred and retested 5 minutes after adding. The results were pH at 8.31 and alkalinity was still 9.0

4) The pH settled out at 8.38 after another 10 minutes and the alkalinity was still 9.0. Total addition of Boost pH+ had been 2 ml.

Here's what it looks like with NaOH on my tank water.
1 Liter tank water. additions of 1.0M NaOH.
Initial pH 7.72
API:
8 drops green, 9 drops yellow
8 green, 9 yellow

Red Sea: 9.1, 9.1 (0.65mL titrant)

added 0.100mL of 1M NaOH so 0.1 meq/L

pH 7.92
API: 8 drops blue-green, 9 drops yellow
Red Sea 9.3-9.4 (0.67mL titrant)

added a second 0.100mL of 1M NaOH so total 0.2meq/L

pH 8.06
API:
8 drops blue-green, 9 drops yellow with a little green
8 blue-green, 9 yellow with a little green

Red Sea: 9.5-9.6, 9.5-9.6 (0.68-0.69mL titrant)

API instructions are "when it goes from blue to yellow", so you could choose to round all those results to "yellow at 9dKH", but if you look at the colors, it's clear there's a difference, but something less than a full drop.

Red Sea Alk works fine for this. The 1.00mL syringe dispensing the titrant is plenty to pick up what is happening. Look at the target color on the card, average the titrant value when the color is just detectably "bluer" than the target color with the titrant volume when it's just detectably "yellower" than the target.

If it's done side by side with the product and NaOH, it should be clear what's going on.

 

[taricha]

BTW, I won't be ordering this product. So other testers will finish this up.
Just wanted to see how well the alk bump shows up on test kits.

 

[MnFish1]

All I sais is that the results could be a defense that the company could use - There is no reason to use API tests here. Before you get upset Randy - I agreed with you - however - there s a difference between actual significance - vs statistical significance - of course, Randy, you are well aware of this concept.

 

[MnFish1]

But that’s with one dose. What happens if dosing overtime? We don’t only want to have a pH of 8.3 for one day. We want to maintain it daily.

An unexpected and unaccounted rise of 0.3dKH per day is substantial.

who would do that?

 

[EeyoreIsMySpiritAnimal]

P

who would do that?

Probably a lot of people. Most don't want to buy a bottle of something to only use once...

 

[Miami Reef]

who would do that?

Why would anyone just want to maintain elevated pH for one day? Do you think corals would grow fast if they only ever got elevated pH for one day? Maybe you just solved the crisis for ocean acidification: just dose Brightwell Boost pH...once.

 

[Garf]

who would do that?

Well, that’s sort of the problem. You are only supposed to use it on tanks that have a low pH due to CO2. That issue tends not to just disappear on its own and if boost + doesn’t increase Alk, users will be in the same boat, tomorrow. Seems like it’s designed for repeat usage, at least until you reach the maximum suggested Alk, when apparently its not such a good idea, according to the sales bumpf.