Alk and Cal consumption

[Dan Ponchak]

I’ve been reefing 5-6 years. 2 part dosing 2-3 years. About 4 months ago my Alk and cal consumption became the same. My tank has never done better. Is this co-incidental ? I know there are lots of other variables to consider, but is there a correlation? Thanks. Dan.

 

[Randy Holmes-Farley Verified Community Expert]

What do you mean it became the same?

Same volume dosed daily?

What product? How much of each?

Not all two parts are designed properly for 1:1 dosing, and a variety of things interfere with that ratio, primarily water changes and rising or falling (or dosing) nitrate.

 

[Dkeller_nc]

I'm going to guess that what you mean is that you've calculated the molar additions of carbonate and calcium to your tank (i.e., the answer to Randy's question is: I'm adding the same molar mass of carbonate and alkalinity, so the additions are "balanced"). And I'm thinking that your question is whether there's a cause and effect of the "tank has never done better" and the balance of consumption of the alkalinity and calcium additions.

In my opinion, the answer is complicated. Just one of those complications is what you mean by the tank "doing better". If the answer is that your coral growth has increased since the additions became balanced, then there is a logical, chemistry explanation. Corals add to their skeletons by using carbonate ions and calcium ions from the water in a 1:1 ratio. In general, the typical processes in a tank would be expected to consume a bit more alkalinity than calcium on a molar basis because nitrification of food and other nutrient additions to the tank consume alkalinity but not calcium.

The catch is that the alkalinity consumption of the nitrate cycle is released back to the water by the denitrification process (the conversion of nitrate to nitrogen gas). With most tanks, denitrification doesn't proceed at the rate that nitrification does, so there's an overall impression of consumption of more alkalinity than calcium, with a concomitant increase in nitrate concentration in the tank water.

So, it well could be that the amount of coral growth in your tank is so high that it dwarfs the consumption of alkalinity due to nitrification, so the alkalinity and calcium consumption appear to be balanced. It's also possible that your tank has developed sufficient denitrification that the nitrate cycle has a net zero consumption of alkalinity.

The answer to your question is therefore "it depends". If the first explanation is correct, and the coral growth greatly eclipses nitrification in your tank, then I'd say that the balance of the alkalinity and calcium consumption is a result of the coral growth, not necessarily the cause of it. If the second explanation is correct (balance due to balancing of the nitrification/denitrification reactions), then I'd say that's an indicator of a maturing tank, and typically mature tanks have healthier coral than newer tanks.

 

[blasterman]

Simple form: alk consumption has slowed down and calcium consumption has increased steadily, right? Yes, this good and indicates your tank biology has stabilized and SPS, provided you have them are likely growing happily. In general, having steady or increasing calcium consumption is a good thing because only things that you paid for are consuming it, unlike alk.

With heavy SPS loads and higher PH levels I've found calcium consumption significantly out strips alk, at least in terms of the rough metrics we use to measure it.

 

[rusgum]

With heavy SPS loads and higher PH levels I've found calcium consumption significantly out strips alk, at least in terms of the rough metrics we use to measure it.
[/QUOTE]
it can't happen

 

[arking_mark]

Simple form: alk consumption has slowed down and calcium consumption has increased steadily, right? Yes, this good and indicates your tank biology has stabilized and SPS, provided you have them are likely growing happily. In general, having steady or increasing calcium consumption is a good thing because only things that you paid for are consuming it, unlike alk.

With heavy SPS loads and higher PH levels I've found calcium consumption significantly out strips alk, at least in terms of the rough metrics we use to measure it.

Again with this? This is not based on any scientific evidence or processes found in reefing.

 

[arking_mark]

Again with this? This is not based on any scientific evidence or processes found in reefing.

Your welcome to finish the discussion started in this thread...

How to balance Ca/Alk in the reef aquarium?

After reading: http://www.reefkeeping.com/issues/2004-12/rhf/ Here are my takeaways: For most practical purposes, Ca and Alk are consumed equally. However, "...the demand for calcium and alkalinity may not be precisely balanced at 20 ppm calcium per 1 meq/l of alkalinity..." The biggest...

www.reef2reef.com

Otherwise, the information you are providing is inaccurate and can cause issues.

 

[Dan Ponchak]

What do you mean it became the same?

Same volume dosed daily?

What product? How much of each?

Not all two parts are designed properly for 1:1 dosing, and a variety of things interfere with that ratio, primarily water changes and rising or falling (or dosing) nitrate.

72 ml dosed daily of each Alk and Cal. B-Ionic 2 part administered by my bubblemagis. I think my dosing pumps might need replaced though. I think that’s a lot for an sps dominant 80 gallon. When those numbers (Alk & cal) became the same the improvement of the tank was noticeable.

 

[Dan Ponchak]

Thank you all for your input. The science you discuss is sometimes beyond my comprehension. Growth, color, overall appearance, all only opinion of my subjective observation. My question was very generalized and intended to solicit other opinion. Correlation or coincidence? Alk and calcium consumption.

 

[Randy Holmes-Farley Verified Community Expert]

Thank you all for your input. The science you discuss is sometimes beyond my comprehension. Growth, color, overall appearance, all only opinion of my subjective observation. My question was very generalized and intended to solicit other opinion. Correlation or coincidence? Alk and calcium consumption.

The answer is simple and is not related to tank "health" (except indirectly, in that as calcification demand in a growing tank rises, the other minor processes described below become less of a part of the total alk demand).

The issue is also not really an opinion.

The main process that uses them uses both equally (2.8 dKH for each 18-20 ppm calcium) is calcium carbonate formation.

Other, usually minor processes use or produce alk (no process uses or adds calcium and not alk).

Rising or falling (or dosing) nitrate adds it or depletes alk, respectively. 2.3 dKH for each 50 ppm of nitrate. Steady nitrate without dosing does nothing to alk.

Sulfur denitrators deplete alkalinity.

Unusual additives can boost alk (such as sodium ascorbate).

Water changes also mess with the apparent demand ratio.

This has more:

When Do Calcium and Alkalinity Demand Not Exactly Balance? by Randy Holmes-Farley - Reefkeeping.com

 

[Dan Ponchak]

Thank you Randy. That was the info I was looking for.

 

[Dan Ponchak]

I'm going to guess that what you mean is that you've calculated the molar additions of carbonate and calcium to your tank (i.e., the answer to Randy's question is: I'm adding the same molar mass of carbonate and alkalinity, so the additions are "balanced"). And I'm thinking that your question is whether there's a cause and effect of the "tank has never done better" and the balance of consumption of the alkalinity and calcium additions.

In my opinion, the answer is complicated. Just one of those complications is what you mean by the tank "doing better". If the answer is that your coral growth has increased since the additions became balanced, then there is a logical, chemistry explanation. Corals add to their skeletons by using carbonate ions and calcium ions from the water in a 1:1 ratio. In general, the typical processes in a tank would be expected to consume a bit more alkalinity than calcium on a molar basis because nitrification of food and other nutrient additions to the tank consume alkalinity but not calcium.

The catch is that the alkalinity consumption of the nitrate cycle is released back to the water by the denitrification process (the conversion of nitrate to nitrogen gas). With most tanks, denitrification doesn't proceed at the rate that nitrification does, so there's an overall impression of consumption of more alkalinity than calcium, with a concomitant increase in nitrate concentration in the tank water.

So, it well could be that the amount of coral growth in your tank is so high that it dwarfs the consumption of alkalinity due to nitrification, so the alkalinity and calcium consumption appear to be balanced. It's also possible that your tank has developed sufficient denitrification that the nitrate cycle has a net zero consumption of alkalinity.

The answer to your question is therefore "it depends". If the first explanation is correct, and the coral growth greatly eclipses nitrification in your tank, then I'd say that the balance of the alkalinity and calcium consumption is a result of the coral growth, not necessarily the cause of it. If the second explanation is correct (balance due to balancing of the nitrification/denitrification reactions), then I'd say that's an indicator of a maturing tank, and typically mature tanks have healthier coral than newer tanks.

Thank you Dkeller. I can’t compliment your answer enough. Easy for me to comprehend

 

[Randy Holmes-Farley Verified Community Expert]

Thank you Randy. That was the info I was looking for.

You're welcome.

Happy Reefing.

 

[blasterman]

Your welcome to finish the discussion started in this thread...

How to balance Ca/Alk in the reef aquarium?

After reading: http://www.reefkeeping.com/issues/2004-12/rhf/ Here are my takeaways: For most practical purposes, Ca and Alk are consumed equally. However, "...the demand for calcium and alkalinity may not be precisely balanced at 20 ppm calcium per 1 meq/l of alkalinity..." The biggest...

www.reef2reef.com

Otherwise, the information you are providing is inaccurate and can cause issues.

You.

Your welcome to finish the discussion started in this thread...

How to balance Ca/Alk in the reef aquarium?

After reading: http://www.reefkeeping.com/issues/2004-12/rhf/ Here are my takeaways: For most practical purposes, Ca and Alk are consumed equally. However, "...the demand for calcium and alkalinity may not be precisely balanced at 20 ppm calcium per 1 meq/l of alkalinity..." The biggest...

www.reef2reef.com

Otherwise, the information you are providing is inaccurate and can cause issues.

What rock do you live under?

How many threads do we get a week with somebody having high alk consumption and low calcium and staring blankly at their dosing bottles? 50?

I don't see you answering them.

As tanks mature and SPS growth picks up...assuming it does ....alkalinity consumption drops relative to calcium. Depending on the tank, age, bio load producing nitrate , and actual rate of growth of SPS the change in ratio can be huge. Higher PH levels promote higher calcification rates....got that...or do I need a white board? If calcification rates increase then the ratio of calcium to alk begin to level because it has ot. However, since we are dealing with variables such as how much baking soda some vendor is putting in a bottle we have no idea what the actual molar amount is....what the OP sees is alk dropping relative to calcium, and Randy just confirmed it.

I think you need a job selling two parts in a marketing dept.

 

[blasterman]

Also, I've asked Randy this same question many times and I've either missed it or he hasn't answered it.

If the tank has a nitrogen cycle it's producing nitrate - period. If the tank is producing nitrate alk ******HAS****** to be being consumed, correct? There is no biological situation is which nitrate is not being produced provided ammonia is being introduced into the tank, correct? If there is a way for ammonia to be fixed out of the water table without producing nitrate in a normal reef tank do tell. The industry along with every water treatment plant wants to know how this miraculous process occurs.

If a tank has a nitrate level of 30 and it doesn't get higher it simply means that nitrate is being consumed fast enough to not be picked up your test kit. That means alk is being sucked up producing this nitrate, correct Randy?

And once again, a half dozen frags in a 125gal tank likely aren't touching calcium...but that same tank is wreaking alk at a massive rate, which corresponds to the countless threads we get....not BRS videos and some dude on your tube with an acropora dominant tank.

 

[arking_mark]

Again. Further in the Nitrogen cycle the Alk is returned to the system to equal the amount consumed. So if you have a steady state...no net change to Alk.

 

[arking_mark]

Non-SPS dominant tanks typically consume Alk/Ca through abiotic precipitation.

My tank without much in it was consuming 1 dKH / 7ppm Ca per day once I got my pH up to 8.3ish. I learned that this is very common.

 

[Randy Holmes-Farley Verified Community Expert]

Also, I've asked Randy this same question many times and I've either missed it or he hasn't answered it.

If the tank has a nitrogen cycle it's producing nitrate - period. If the tank is producing nitrate alk ******HAS****** to be being consumed, correct? There is no biological situation is which nitrate is not being produced provided ammonia is being introduced into the tank, correct? If there is a way for ammonia to be fixed out of the water table without producing nitrate in a normal reef tank do tell. The industry along with every water treatment plant wants to know how this miraculous process occurs.

If a tank has a nitrate level of 30 and it doesn't get higher it simply means that nitrate is being consumed fast enough to not be picked up your test kit. That means alk is being sucked up producing this nitrate, correct Randy?

And once again, a half dozen frags in a 125gal tank likely aren't touching calcium...but that same tank is wreaking alk at a massive rate, which corresponds to the countless threads we get....not BRS videos and some dude on your tube with an acropora dominant tank.

I've answered this many times.

Ammonia released by metabolism (fish, bacteria, whatever) and then converted to nitrate consumes 2.3 dKH per 50 ppm of nitrate produced

Nitrate consumed and used to produce tissue or ammonia or N2 gas releases 2.3 dKH of alkalinity for each 50 ppm of nitrate consumed.

Thus, if nitrate is steady at any level, the biological processes related to it are neither adding nor consuming alkalinity.

 

[Randy Holmes-Farley Verified Community Expert]

When nitrate is rising, alk is being consumed.

When nitrate is falling (or being dosed), alk is being added

 

[blasterman]

I've answered this many times.

Ammonia released by metabolism (fish, bacteria, whatever) and then converted to nitrate consumes 2.3 dKH per 50 ppm of nitrate produced

Nitrate consumed and used to produce tissue or ammonia or N2 gas releases 2.3 dKH of alkalinity for each 50 ppm of nitrate consumed.

Thus, if nitrate is steady at any level, the biological processes related to it are neither adding nor consuming alkalinity.

No, you haven't answered it.

Please tell me how a tank with organisms producing ammonia aren't producing nitrate.

Maybe that nitrate is going to another dimension?

Basically the hypocrisy here is we claim our calcium test kits aren't accurate enough to detect precise levels of calcium to justify two part dosing...but our nitrate test kits are capable of measuring precise levels of nitrate.

Not arguingwith your Randy, but you are missing my question.