All for Reef Dosing Calculation Help

[arking_mark]

I'm using the DIY All-for-Reef which uses 140g of Carbocalcium. Per tropic Marin, "100 g (3.5 oz.) of Carbocalcium Powder containing more than 30,000 mg of calcium and more than 4,000 °dH."

So, 140g of Carbocalcium used in the DIY contains 1.4 x 4000dKH = 5600dKH in 1000ml solution.

To raise a 100L tank by 1dKH, you would need 100/5599 = 0.018L or 18ml

To raise a 100L tank by 0.1dKH, you would use 1.8ml

To raise my 400L tank by 0.1dKH, I would add 4 x 1.8 = 7.2ml

Did I get this correct?

 

[arking_mark]

Follow-up question on this. For the last couple of weeks, my dKH has been slowly falling by about 0.1dKH per day. So I decided to use AFR for this replacement as I was at my Kalk dosing limit. I got unexpected results and hence wanted to verify the dosing amount.

I did my initial 7ml dose on Wednesday night and then another 7ml dose on Thursday night. My Alk jumped from 7.6 to 8.4.

Obviously, I'm going to discontinue dosing AFR until the dosing amount is verified and I can get the expected results.

 

[Daftendire]

I do not know the measurements you need but I just started dosing AFR on my 35g nano and can share a similar experience.

Dosed the starting recommended amount for a 25g tank per the bottle instructions: 5ml/day. Within a week my alk went from 7.8 to 9.3 (should have tested sooner). I use IO salt which mixes at around that level anyway. I have since cut way back on the dose... Currently less than 1ml/day.

 

[arking_mark]

I do not know the measurements you need but I just started dosing AFR on my 35g nano and can share a similar experience.

Dosed the starting recommended amount for a 25g tank per the bottle instructions: 5ml/day. Within a week my alk went from 7.8 to 9.3 (should have tested sooner). I use IO salt which mixes at around that level anyway. I have since cut way back on the dose... Currently less than 1ml/day.

7.8 + .28*7 = 9.8

I think your Alk consumption is not that high in your tank. Looks more like .5dKH per week or roughly 9ml of solution per week.

 

[Randy Holmes-Farley]

I'm using the DIY All-for-Reef which uses 140g of Carbocalcium. Per tropic Marin, "100 g (3.5 oz.) of Carbocalcium Powder containing more than 30,000 mg of calcium and more than 4,000 °dH."

So, 140g of Carbocalcium used in the DIY contains 1.4 x 4000dKH = 5600dKH in 1000ml solution.

To raise a 100L tank by 1dKH, you would need 100/5599 = 0.018L or 18ml

To raise a 100L tank by 0.1dKH, you would use 1.8ml

To raise my 400L tank by 0.1dKH, I would add 4 x 1.8 = 7.2ml

Did I get this correct?

Before checking the math, remember that the alk in carbo calcium (formate) will not show up as alkalinity unless and until something metabolizes it and releases the alk back to the water. For that reason, dosing by calcium demand, while much less sensitive, may make more sense and was suggested by Lou Ekus.

Also bear in mind the "more than" statements above.

140 grams of 10)% calcium formate (assuming it is fully dry) contains 1.077 moles (43.1 g) of calcium and 2.15 moles of formate.

If you dissolve that in 1 L of water, the concentration is 43,000 ppm calcium and 6,000 dKH.

To raise a 100L tank by 1dKH, you would need 100/6000 = 0.0167 L or 16.7 ml

To raise a 100L tank by 0.1dKH, you would use 1.7 ml

To raise my 400L tank by 0.1dKH, I would add 4 x 1.7 = 6.7 ml

 

[arking_mark]

Before checking the math, remember that the alk in carbo calcium (formate) will not show up as alkalinity unless and until something metabolizes it and releases the alk back to the water. For that reason, dosing by calcium demand, while much less sensitive, may make more sense and was suggested by Lou Ekus.

Also bear in mind the "more than" statements above.

140 grams of 10)% calcium formate (assuming it is fully dry) contains 1.077 moles (43.1 g) of calcium and 2.15 moles of formate.

If you dissolve that in 1 L of water, the concentration is 43,000 ppm calcium and 6,000 dKH.

To raise a 100L tank by 1dKH, you would need 100/6000 = 0.0167 L or 16.7 ml

To raise a 100L tank by 0.1dKH, you would use 1.7 ml

To raise my 400L tank by 0.1dKH, I would add 4 x 1.7 = 6.7 ml

So you've nailed why I have unexpected results. I was expecting AFR to just offset my slow decline in Alk. Due to the fact that this needs to be either consumed directly by coral or metabolized, I wasn't expecting a sharp increase in Alk. Even more surprising was the how much it increased per how little AFR was being used (even by your estimates).

I keep my tank at 8.32-8.37pH day and night. I'm dosing 1dKH worth of Kalk.

My tank just really has frags at this point, and should be low demand. I theorize that most of the Alk/Ca consumption is abiotic.

Could the Calcium Formate interfere with the abiotic demand? If so, that would explain the rapid increase in Alk.

 

[arking_mark]

@Lou Ekus Any insight?

 

[arking_mark]

Also note, I found the abiotic precipitation...clumping sand.

 

[Hans-Werner]

So I decided to use AFR for this replacement as I was at my Kalk dosing limit.

Hello,

Are you still dosing Kalkwasser? Maybe the bicarbonate produced from the formate is interfering with the Kalkwasser making it more efficient.

As you and Randy have calculated the increase in alkalinty exceeds the expected supply of All-For-Reef by far.

Clumping sand may be the result of dosing Kalkwasser. I have experienced it myself and other reef aquarists also that Kalkwasser may form a solid rock with coral sand.

Clumping sand from All-For-Reef alone is chemically very unlikely and we have no other reports about it.

 

[arking_mark]

Hello,

Are you still dosing Kalkwasser? Maybe the bicarbonate produced from the formate is interfering with the Kalkwasser making it more efficient.

As you and Randy have calculated the increase in alkalinty exceeds the expected supply of All-For-Reef by far.

Clumping sand may be the result of dosing Kalkwasser. I have experienced it myself and other reef aquarists also that Kalkwasser may form a solid rock with coral sand.

Clumping sand from All-For-Reef alone is chemically very unlikely and we have no other reports about it.

Yeah. I'm sure the AFR has nothing to do with the clumping sand as I was just starting to dose AFR.

@Hans-Werner When you say making Kalkwasser more efficient, what does that mean?

I've been reading up on the pH/Alk relationship. I have basically locked in my pH at 8.3 with a CO2 scrubber and oversized Skimmer (plus Kalk and reverse light cycle refugium). So my Alk should move up and down the blue line I drew (if my understanding is correct):

Previously, I was running at a pH 8.35, with an Alk at 8.6 which was coming down by about 0.1dKH a day. So looking at the above chart (red line) I was driving my CO2 below normal to maintain my pH. I added 7ml on two consecutive days of AFR and my Alk jumped back to 8.4 (3meq/l). Again, since I'm locking in pH, I think AFR impacted water CO2 or the abiotic precipitation which moved up my Alk.

Based on the above chart, with my 8.3pH, I should be targeting a 7.7ish dKH. Since my Alk is at 8.4dKH (3meq/l), my CO2 levels are now slightly elevated.

@Randy Holmes-Farley I hope you don't mind that I used your chart...and maybe butchered the chemistry.

 

[ReefBeta]

Even though the alk affect of calcium formate is delayed, when combing with other dosing, the affect shows up really fast. Possibly because, when those got used by coral directly, the consumption of the free form alkalinity got left in the water column and showed up on tests.

As of how much to dose, I think it's easier to just look at the tests. Start from 0, if alkalinity drops, up dosing by couple ml, wait for a day. If it rise, drop the dose a bit. That's basically what I do in my tank, adjust when it's going down or up for a day or two. It converge to a point relatively fast, within a week.

 

[Hans-Werner]

When you say making Kalkwasser more efficient, what does that mean?

This means for example by buffering at a lower pH.

What is limiting the efficiency of Kalkwasser is, besides the concentration, the pH shift. Event if evaporation is sufficient to replace calcium and alkalinity with Kalkwasser the pH rise may limit the calcium and alkalinity supply with Kalkwasser.

Kalkwasser converts bicarbonate to carbonate by supplying hydroxide ions.

OH- + (HCO3)- --> (CO3)2- + H2O

By this conversion the water gets oversaturated with calcium carbonate which may precipitate

By adding for example CO2 carbonate gets converted back to bicarbonate

(CO3)2- + CO2 + H2O --> 2 (HCO3)-

In this way addition of CO2 is making Kalkwasser more efficient, for example.

 

[arking_mark]

This means for example by buffering at a lower pH.

What is limiting the efficiency of Kalkwasser is, besides the concentration, the pH shift. Event if evaporation is sufficient to replace calcium and alkalinity with Kalkwasser the pH rise may limit the calcium and alkalinity supply with Kalkwasser.

Kalkwasser converts bicarbonate to carbonate by supplying hydroxide ions.

OH- + (HCO3)- --> (CO3)2- + H2O

By this conversion the water gets oversaturated with calcium carbonate which may precipitate

By adding for example CO2 carbonate gets converted back to bicarbonate

(CO3)2- + CO2 + H2O --> 2 (HCO3)-

In this way addition of CO2 is making Kalkwasser more efficient, for example.

In my tank, I am controlling pH and keeping it locked in at 8.3. I am definitely getting abiotic precipitation as seen by clumping sand.

Now I think I understand what happens when I have let the tank pH drop. The CO2 goes up, tank saturation can increase and I see much higher Alk/Ca.

So with my current setup, most of my Alk/Ca consumption is probably abiotic precipitation.

So by adding AFR, which is also a form of carbon dosing, CO2 is produced? Thereby increasing Alk/Ca?

 

[Hans-Werner]

Yes, I agree.

So by adding AFR, which is also a form of carbon dosing, CO2 is produced? Thereby increasing Alk/Ca?

That is a very good question. The mere oxidation of formate should produce bicarbonate only.

(HCO2)- + 1/2 O2 --> (HCO3)-

However, if you look at the biochemistry, CO2 results:

(HCO2)- + NAD+ --> CO2 + NADH + H+

But this is only one reaction, while metabolism usually is a whole chain of reactions and this does not completely describe and explain what really gets in and out of the bacteria and yeasts doing this process. Where does the NAD+ and its charge come from?

In my opinion an organisms has to do processes electrically neutral since it is not an accumulator with continuously increasing charge. What gets in has to get out. If a cation gets in a cation has to get out, if a neutral molecule gets in a neutral molecule has to get out.

So I can't tell exactly what the answer to your question really is.

 

[arking_mark]

Yes, I agree.

That is a very good question. The mere oxidation of formate should produce bicarbonate only.

(HCO2)- + 1/2 O2 --> (HCO3)-

However, if you look at the biochemistry, CO2 results:

(HCO2)- + NAD+ --> CO2 + NADH + H+

But this is only one reaction, while metabolism usually is a whole chain of reactions and this does not completely describe and explain what really gets in and out of the bacteria and yeasts doing this process. Where does the NAD+ and its charge come from?

In my opinion an organisms has to do processes electrically neutral since it is not an accumulator with continuously increasing charge. What gets in has to get out. If a cation gets in a cation has to get out, if a neutral molecule gets in a neutral molecule has to get out.

So I can't tell exactly what the answer to your question really is.

Very interesting. So a little trial and error for each tank to see what works.

 

[Hans-Werner]

In my opinion it is reproducible and very similar to the Balling Method with trace elements.

Slight differences are observed in different tanks with all kinds of calcium and alkalinity supplementation, no matter whether calcium formate, calcium chloride and sodium bicarbonate/carbonate or CO2 coral rubble reactor.

I have even heard the speculation that a CO2 coral rubble reactor may provide more calcium or more alkalinity, depending from the CO2 supply. This should be impossible since the ionic crystal always delivers both in equal quantities. It is impossible that more calcium or more carbonate is dissolved from the ionic crystal.

 

[arking_mark]

Well, the plan for now is to slow down abiotic precipitation, so:
1. Reduce pH to 8.3 [done]
2. Reduce Kalk dosing to slowly bring Alk to 7.7ish [in progress]

I may further reduce pH and/or kalk dosing.

If CO2 scrubber is able to keep up pH as I reduce kalk, I may switch to using some AFR.

 

[Randy Holmes-Farley]

I theorize that most of the Alk/Ca consumption is abiotic.

Could the Calcium Formate interfere with the abiotic demand? If so, that would explain the rapid increase in Alk.

If it is not metabolized to bicarbonate and carbonate, yes, it will reduce precipitation tendency. But in that case it also does not show on an alk test.

 

[arking_mark]

If it is not metabolized to bicarbonate and carbonate, yes, it will reduce precipitation tendency. But in that case it also does not show on an alk test.

@Randy Holmes-Farley I'm a little confused.
1. Tank is consuming 1.1dkh mostly through abiotic precipitation.
2. I'm adding 1dKH work of Kalk
3. I add 0.1dKH of AFR

My expected results would be to see my Alk more stabilized as the AFR formate gets metabolized.

My actual results were a large jump in Alk.

If AFR interferes with abiotic precipitation or increases my CO2 , that would explain the Alk jump.

When I say interferes, here, I mean that the Kalk dosing that is driving abiotic precipitation isn't happening as much and that Alk is now staying in the water column driving up my measured Alk.

 

[arking_mark]

@Randy Holmes-Farley @Hans-Werner

How much (if any) should I dose AFR to stabilize my dKH?

Summary:
1. Tank was at pH 8.35, dosing evaporation limit of Kalk 1dKH, and was seeing a slow but steady 0.1dKH drop per day over two weeks (8.7 --> 7.4)
2. Started dosing 0.1dKH per day of AFR. After 2 doses my dKH jumped from 7.4 -->8.4 in 48hrs (unexpected!)
3. Discontinued AFR, dropped my pH to 8.3, and reduced my Kalk to 0.9dKH per day
4. In 4 days, my dKH is now down to 7.8. So dropping as expected.

I would like to stabilize around this 7.7dKHish. If I bump my Kalk dosing back to 1dKH, I'm pretty sure I will continue to see a slow 0.1 decrease in dKH per day.

@Randy Holmes-Farley If I understand your articles on pH/Ca/Alk/Mag in the saltwater aquarium. With pH, Alk, and air CO2, given any 2 of these numbers, I should be able to calculate the 3rd. So with a fixed pH of 8.3 and a dKH of 7.8 my air CO2 should be very close to 350. (I couldn't find your equation and just eyeballed your graph). Recall that I basically maintain my pH via CO2 scrubber and can drive H out. Hence why I would like to stabilize near these numbers.

The other options:
1. Let the dKH drop which should reduce abiotic precipitation. I believe that this would result in the CO2 scrubber driving out H below 350 to maintain pH. Corals might also not be as happy.
2. Lower my pH along with the drop in Alk. Say pH 8.2 and Alk at 7ish which would again be in line with your graph.

@Randy Holmes-Farley Curious if I'm thinking about this the right "chemistry way" or not.

@Hans-Werner Really would like to take advantage of AFR to stabilize my tank.

I basically can dial in my pH to +/- 0.02. Not sure that a good thing or not...as it really just plays with the CO2 balance if I'm not mistaken.