Bolus dosing

[Featherweight]

Don’t let it. Just ignore it?

You sure do talk a lot. This makes less sense than Claude's explanations. Why do you talk so much?

 

[Garf]

Never-mind, scrubbed.

 

[Mo.]

You sure do talk a lot. This makes less sense than Claude's explanations. Why do you talk so much?

Yeah, sure! You do the talking.!

Oh wait……

 

[Vrolikii]

It is. I’m not understanding how that makes a difference in the bolus pH boost Welsh Reefer sees.

But not even FM/Claude claims that the traces contribute in any way to the pH boost?
I guess what was mentioned, is a benefit of dosing halogens together with the alk bolus before start of the light period, to have maximum concentrations of halogens during the intensity peak of the Bolus Schedule.
Whether this really makes a difference...

 

[Hans-Werner]

In those days the only person doing it was Ehsan from Triton and his tank at the time was just different. Maybe it was the traces don’t know.

Ehsan from Triton was the only one doing what? Trace element dosing?

I published a formula for trace element dosing in 1995/1996 in a German aquarium magazine. After this publication several new companies with trace element dosing popped up in Germany, Korallenzucht, Fauna Marin and others. There has been a history of trace element dosing in Germany before Triton. There even was a controversy about the publications of Shimek which were contradictionary to trace element dosing, all before Triton. Triton was more likely the result of trace element dosing than its inventor.

 

[Mo.]

Ehsan from Triton was the only one doing what? Trace element dosing?

I published a formula for trace element dosing in 1995/1996 in a German aquarium magazine. After this publication several new companies with trace element dosing popped up in Germany, Korallenzucht, Fauna Marin and others. There has been a history of trace element dosing in Germany before Triton. There even was a controversy about the publications of Shimek which were contradictionary to trace element dosing, all before Triton. Triton was more likely the result of trace element dosing than its inventor.

Sorry, I should have been more precise. I meant icp for traces. At least he was the first I knew of that was pushing icp in reefkeeping.

I know your history in trace elements well.

 

[Hans-Werner]

Sorry, I should have been more precise. I meant icp for traces. At least he was the first I knew of that was pushing icp in reefkeeping.

I know your history in trace elements well.

Yes, this is why I asked. I think regarding commercial ICP-OES use you are right. I think it is his merit that ICP-OES in reefkeeping is where it is now. Before Triton ICP-OES was said to be not precise enough. There was a lot of progress since then.

To be clear, I wasn't the inventor of trace element dosing either, I just put it on a different more scientific foundation.

 

[Mo.]

Yes, this is why I asked. I think regarding commercial ICP-OES use you are right. I think it is his merit that ICP-OES in reefkeeping is where it is now. Before Triton ICP-OES was said to be not precise enough. There was a lot of progress since then.

To be clear, I wasn't the inventor of trace element dosing either, I just put it on a different more scientific foundation.

From what I had read, I think your involvement was pivotal.

Similarly Ehasan’s involvement in icp has taken the hobby a long way.

 

[twentyleagues]

It is. I’m not understanding how that makes a difference in the bolus pH boost Welsh Reefer sees.

So I was wondering the same thing. Are you saying there is nothing in the trace that gets added to the Bolus alk dose that could cause the ph boost? I am not a chemist. I get these traces are tiny amounts and given the volume they are dosed probably couldnt or wouldnt effect ph on that large of a scale.

Something has to be causing all the Bolusites to be seeing these changes out of the norm of typical understanding. Is it just faith?

 

[Randy Holmes-Farley]

But not even FM/Claude claims that the traces contribute in any way to the pH boost?
I guess what was mentioned, is a benefit of dosing halogens together with the alk bolus before start of the light period, to have maximum concentrations of halogens during the intensity peak of the Bolus Schedule.
Whether this really makes a difference...

It also seems unlikely to me, but I cannot entirely discount what a burst of trace elements means to photosynthesizing organisms..

What do I seriously think is going on (I know everyone cares, lol)

1. Bicarbonate has the expected immediate effect in every tank using it:

A small pH drop on addition, and if there is sufficient aeration, the tank blows off some of the excess CO2 from the bicarbonate added, raising pH by an amount related to the degree of gas exchange, but limited to the expected new equilibrium value between pH and total alk and the CO2 level in the air used for aeration (something which can be calculated or measured in a beaker (which has been done)).

2. Bicarbonate dosing schemes do not impact pH long term except in how they impact alkalinity at different times of the day. Longer terms effects on pH are unrelated to the choice of how bicarbonate is dosed, but is related to the overall alk, photosynthesis extent (a complicated factor that might be related to many things, including alkalinity, pH, trace element supply, lighting time and intensity, amount of pest algae, etc.), respiration extent (which relates to amounts and types of foods added, among other things), aeration extent, CO2 levels in home air and air used for aeration, and other additives used. I think it is very hard for any reef tank to control each and every one of these for weeks at a time to then say the only thing that could possible explain any results is the change in timing of bicarbonate additions.

In the case of Welsh Reefer's stated experience, I suspect, but obviously cannot prove after the fact, that the change he saw was caused by changes in something in #2. Might have been from the trace elements added impacting photosynthesis, or might have been any of the many other thigns noted to alter pH.

In the case of Mo or anyone else suggesting a long term change in pH, I expect it relates to the known processes in #2 and not some hitherto unknown aspects of bicarbonate in reef tanks.

3. Regarding the table top alk claims and observations, I think there's not enough comparative data of other sorts of alk additives or other dosing schemes of bicarbonate to say whether there's anything unusual or unexpected in the way alk changes through the day when bolus dosing bicarbonate. I agree that some folks might not have expected the table top effect, but is that because the expectation was wrong for when exactly alk is taken up in various scenarios, or something was chemically different? I do strongly believe there's no reason to think the alk is not all immediately available and testable after dosing bicarbonate in any way, as long as one does not cause significant precipitation of calcium carbonate.

 

[Garf]

It also seems unlikely to me, but I cannot entirely discount what a burst of trace elements means to photosynthesizing organisms..

What do I seriously think is going on (I know everyone cares, lol)

1. Bicarbonate has the expected immediate effect in every tank using it:

A small pH drop on addition, and if there is sufficient aeration, the tank blows off some of the excess CO2 from the bicarbonate added, raising pH by an amount related to the degree of gas exchange, but limited to the expected new equilibrium value between pH and total alk and the CO2 level in the air used for aeration (something which can be calculated or measured in a beaker (which has been done)).

2. Bicarbonate dosing schemes do not impact pH long term except in how they impact alkalinity at different times of the day. Longer terms effects on pH are unrelated to the choice of how bicarbonate is dosed, but is related to the overall alk, photosynthesis extent (a complicated factor that might be related to many things, including alkalinity, pH, trace element supply, lighting time and intensity, amount of pest algae, etc.), respiration extent (which relates to amounts and types of foods added, among other things), aeration extent, CO2 levels in home air and air used for aeration, and other additives used. I think it is very hard for any reef tank to control each and every one of these for weeks at a time to then say the only thing that could possible explain any results is the change in timing of bicarbonate additions.

In the case of Welsh Reefer's stated experience, I suspect, but obviously cannot prove after the fact, that the change he saw was caused by changes in something in #2. Might have been from the trace elements added impacting photosynthesis, or might have been any of the many other thigns noted to alter pH.

In the case of Mo or anyone else suggesting a long term change in pH, I expect it relates to the known processes in #2 and not some hitherto unknown aspects of bicarbonate in reef tanks.

3. Regarding the table top alk claims and observations, I think there's not enough comparative data of other sorts of alk additives or other dosing schemes of bicarbonate to say whether there's anything unusual or unexpected in the way alk changes through the day when bolus dosing bicarbonate. I agree that some folks might not have expected the table top effect, but is that because the expectation was wrong for when exactly alk is taken up in various scenarios, or something was chemically different? I do strongly believe there's no reason to think the alk is not all immediately available and testable after dosing bicarbonate in any way, as long as one does not cause significant precipitation of calcium carbonate.

I had a poke around with a CO2 calculator earlier regarding an earlier statement you made about how the impact of Alk additions can change with starting pH. Sure enough, the lower the pH of the aquarium, the greater the impact of Alk additions on pH. This appears to be a benefit of deminishing returns as the low pH increases.

 

[Randy Holmes-Farley]

I had a poke around with a CO2 calculator earlier regarding an earlier statement you made about how the impact of Alk additions can change with starting pH. Sure enough, the lower the pH of the aquarium, the greater the impact of Alk additions on pH. This appears to be a benefit of deminishing returns as the low pH increases.

Yes, the reason is that the water is buffered more strongly at higher pH due to getting closer to the max pH buffering point of

HCO3- <--> H+ + CO3--

That max buffering point, as it is with all buffers, is at the pKa of bicarbonate (point of equal carbonate and bicarbonate), which is about 8.55 in seawater.

It takes almost 3 times as much acid or base to move pH by 0.1 pH unit at pH 8.55 as it does at pH 7.8.

Chemistry And The Aquarium: Boron In A Reef Tank

This article also discusses the sources and sinks for boron in reef tanks, and shows that while typical tanks may be slightly depleted in boron with respect to natural levels, most are not so significantly depleted that any correction is required. Nevertheless, how to test for and supplement...

reefs.com

 

[Garf]

Yes, the reason is that the water is buffered more strongly at higher pH due to getting closer to the max pH buffering point of

HCO3- <--> H+ + CO3--

That max buffering point, as it is with all buffers, is at the pKa of bicarbonate (point of equal carbonate and bicarbonate), which is about 8.55 in seawater.

It takes almost 3 times as much acid or base to move pH by 0.1 pH unit at pH 8.55 as it does at pH 7.8.

Chemistry And The Aquarium: Boron In A Reef Tank

This article also discusses the sources and sinks for boron in reef tanks, and shows that while typical tanks may be slightly depleted in boron with respect to natural levels, most are not so significantly depleted that any correction is required. Nevertheless, how to test for and supplement...

reefs.com

It's no problem that this effect is short lived, just add more light,(waiting 10 the 30 minutes before a light blast should do it), lol.

 

[rishma]

hitherto unknown aspects of bicarbonate in reef tanks.

 

[Randy Holmes-Farley]

Not a word I commonly use, but it seemed appropriate. lol

 

[Mo.]

Randy,

What are your thoughts about this?

A pulse of bicarbonate will push the instantaneous alkalinity up, with a corresponding small spike in pH (accepting the initial drop in pH)

I suspect (or have seen) a pulse will have a greater point effect on pH than multiple small doses throughout the day (which cause a very small change in pH each time).

As lighting comes on, the pH can be sustained by photosynthesis.

I suspect that if the pulse gives a sufficient boost to pH, the higher pH will resist a change downwards at lights out.
Ie the buffering capacity of the bicarbonate at the higher pH is better and will more resist downward change.

I guess the max pH obtainable by bicarbonate dosing is equivalent to the pKa ie 8.55 or so due to the buffering capacity?

As I have noticed a gradual rise in pH by bolus dosing the alk, can it be that the pH spike we see after the bolus is buffered to allow a cumulative rise towards the pKa and the closer it gets the more stable the pH and alk becomes?

Can that even partly explain the observed pH rise that some see with bolus?

 

[Hats_]

As i see it, and i acknowledge my chemical know how is limited, by dosing all your alk at once vs keeping it stable you risk a lower pH at night due to the lower alk. Say you keep your alk at 7 but your consumption is 2 per day. At the end of the day your alk will be 5 since you only dose once in the morning. This leaves a lowering buffering capacity than having it still at 7 at the end of the day by dosing throughout the day

 

[Randy Holmes-Farley]

The effect on pH for total alk is not dependent on whether the alk spikes to that alk, or is stable there. There is no max to the pH that is obtainable from total alk and aeration except as other process begin to limit it, such as precipitation of calcium carbonate.

 

[Garf]

Randy,

What are your thoughts about this?

A pulse of bicarbonate will push the instantaneous alkalinity up, with a corresponding small spike in pH (accepting the initial drop in pH)

I suspect (or have seen) a pulse will have a greater point effect on pH than multiple small doses throughout the day (which cause a very small change in pH each time).

As lighting comes on, the pH can be sustained by photosynthesis.

I suspect that if the pulse gives a sufficient boost to pH, the higher pH will resist a change downwards at lights out.
Ie the buffering capacity of the bicarbonate at the higher pH is better and will more resist downward change.

I guess the max pH obtainable by bicarbonate dosing is equivalent to the pKa ie 8.55 or so due to the buffering capacity?

As I have noticed a gradual rise in pH by bolus dosing the alk, can it be that the pH spike we see after the bolus is buffered to allow a cumulative rise towards the pKa and the closer it gets the more stable the pH and alk becomes?

Can that even partly explain the observed pH rise that some see with bolus?

Your Alk consumption has increased from 0.4 to 1 DKH. This alone shows an increase in photosynthesis is likely, nevermind the thousands of other variables. For example, you say you are feeding shed loads, does this mean the tangs have stopped scavenging the rocks? Have your snails bit the dust? Has water clarity increased? Were you previously nutrient limited? The list goes on. Did you find a reason for the temperature difference in your sump, compared to the tank?

 

[rtparty]

@Randy Holmes-Farley

Just to clarify in case I missed it…

When Bolus dosing bicarbonate, the pH of the bicarbonate is mid 8s? Like 8.5 or so? It is being dosed usually into the sump where the pH probe is located. This creates a momentary pocket of “high alkalinity, high pH” seawater, correct? This then reaches the pH probe and looks like a spike. It then takes “about 10 minutes” to come back down. Did anyone ever clarify how often their pH probes are reading and plotting the numbers?

Is it not entirely possible that the pH spike is simply a false reading and by the time the probe tracks and plots a change the bicarbonate has thoroughly mixed with the tank, shot up alkalinity, and thus ticked pH up slightly higher than it was before the dose?

Hopefully I spelled that out to make sense