No calcium dosing? Only ALK

[Daniel91]

In my IM20, I dose 2.5ml/day of 2part to maintain my alkalinity around 7.5-8.0.

When I started, I was dosing equal parts of calcium too but quickly noticed that my calcium was only increasing. I stopped dosing calcium altogether and have only been dosing alkalinity for a month.

Per my last three tests, calcium has been around 465-480 and no signs of decreasing, despite a weekly 5G ~20% WC with salt mixed at 430 calcium and 8 alk.

I am going to continue just dosing alkalinity (unless your input suggest otherwise), but wanted to understand why my calcium is not decreasing? I have plenty of corals; mixed with noticeable growth.

 

[ScottB]

In my IM20, I dose 2.5ml/day of 2part to maintain my alkalinity around 7.5-8.0.

When I started, I was dosing equal parts of calcium too but quickly noticed that my calcium was only increasing. I stopped dosing calcium altogether and have only been dosing alkalinity for a month.

Per my last three tests, calcium has been around 465-480 and no signs of decreasing, despite a weekly 5G ~20% WC with salt mixed at 430 calcium and 8 alk.

I am going to continue just dosing alkalinity (unless your input suggest otherwise), but wanted to understand why my calcium is not decreasing? I have plenty of corals; mixed with noticeable growth.

I've not bothered to do the math on it, but my ALK consumption is several times higher than calcium. I just keep dosing equal parts anyway. I don't test Ca much, it always the same ~480. Ditto with Mg at 1380.

If my dose container goes dry, I will lose at least 1 dkh in a day. But the other two don't really move. So your experience is not that much different than mine.

 

[Miller535]

following

 

[Rybren]

According to Randy, calcium will only drop about 18-20ppm for every 2.8 dKH of alk used. It sounds like you're not using much alk, so it will take some time before a calcium drop will be discernible.

 

[Randy Holmes-Farley]

Many salt mixes have excess calcium and water changes with them can make it appear that only alk is depleting when In fact, they are depleting together as expected.

The main other way alk depletes that doesn’t not involve calcium us by rising nitrate, which depletes alkalinity.

Also note that many products are not designed (or properly designed) for 1:1 dosing. Many of those folks don’t realize this and then tell others that their demand is unbalanced when it is not.

Finally, when demand is very low (< 0.5 dKH per day) the small deviations caused by water changes and nitrate issues take on a much bigger portion of the total demand, changing the apparent demand ratio far more than it could in a high demand aquarium using 2+ dKH per day.

 

[Randy Holmes-Farley]

I've not bothered to do the math on it, but my ALK consumption is several times higher than calcium. I just keep dosing equal parts anyway. I don't test Ca much, it always the same ~480. Ditto with Mg at 1380.

If my dose container goes dry, I will lose at least 1 dkh in a day. But the other two don't really move. So your experience is not that much different than mine.

I’m confused. At 1 dKH per day, a properly designed two part will add about 6-7 ppm of calcium per day. Magnesium consumption will be less than 0.5 ppm per day.

If calcium is stable dosing 1:1, why do you say the alk consumption is several times higher than calcium? Your result would seem to fit the definition of demand Matching what is dosed.

 

[ScottB]

I’m confused. At 1 dKH per day, a properly designed two part will add about 6-7 ppm of calcium per day. Magnesium consumption will be less than 0.5 ppm per day.

If calcium is stable dosing 1:1, why do you say the alk consumption is several times higher than calcium? Your result would seem to fit the definition of demand Matching what is dosed.

Uh oh. If you are confused, how do you think I feel?

I appreciate the ppm comparisons you just gave for calcium and magnesium. Is there a comparable daily ppm consumption number for alkalinity? If there is, my theory is that it is several times higher than that of Ca and Mg. How does dKH get translated into daily ppm consumption of ESV Part A?

If your answer involves an equation with >2 Greek letters, then just say "You wouldn't understand." You won't be wrong, nor I offended.

 

[Randy Holmes-Farley]

Uh oh. If you are confused, how do you think I feel?

I appreciate the ppm comparisons you just gave for calcium and magnesium. Is there a comparable daily ppm consumption number for alkalinity? If there is, my theory is that it is several times higher than that of Ca and Mg. How does dKH get translated into daily ppm consumption of ESV Part A?

If your answer involves an equation with >2 Greek letters, then just say "You wouldn't understand." You won't be wrong, nor I offended.

The numbers I gave are all a relative ratio alkalinity : calcium : magnesium
which is about
2.8 dKH alkalinity : 18-20 ppm calcium :00-2 ppm magnesium

I just adapted the ratio to your alkalinity consumption of 1 dKH per day to get:

1 dKH alkalinity : 6-7 ppm calcium : <1 ppm magnesium

 

[Daniel@R2R]

Helpful info! Thanks Randy!

 

[billwill]

When I used to dose two part, I never dosed equal amounts. You've got to dose each based on what your testing reflects and what balance point you're starting from/trying to maintain.

 

[Belgian Anthias]

If nitrification takes place on a base of aragonite or another calcium carbonate substrate the nitrification process will not consume alkalinity and produce calcium. The nitrification process will use the released carbonate. ref: https://www.baharini.eu/baharini/do...hemie:biofilm#kalk_als_drager_voor_de_biofilm
For lowering calcium one may grow and harvest Halimeda.

 

[Randy Holmes-Farley]

If nitrification takes place on a base of aragonite or another calcium carbonate substrate the nitrification process will not consume alkalinity and produce calcium. The nitrification process will use the released carbonate. ref: https://www.baharini.eu/baharini/do...hemie:biofilm#kalk_als_drager_voor_de_biofilm
For lowering calcium one may grow and harvest Halimeda.

Yes, you can possibly offset the depletion of alkalinity in nitrification by getting the acid produced to dissolve calcium carbonate. That shifts the imbalance from lowering alk and unchanged calcium to unchanged alk and rising calcium.

It is just like adding more of both parts of any balanced two part additive to offset the alk drop, and I see little benefit to trying to rig up a system to do it that way instead of just dosing alk.

 

[Belgian Anthias]

Yes, you can possibly offset the depletion of alkalinity in nitrification by getting the acid produced to dissolve calcium carbonate. That shifts the imbalance from lowering alk and unchanged calcium to unchanged alk and rising calcium.

It is just like adding more of both parts of any balanced two part additive to offset the alk drop, and I see little benefit to trying to rig up a system to do it that way instead of just dosing alk.

Remineralization including nitrification takes place everywhere, on any substrate. These processes will rig up the balance anyway. Using a simple biofilter makes active nutrient management possible and the ideal substrate can be provided. pH will be buffered better as most acids will be used in the filter and the carbon source is retrieved from the calcium-carbonate substrate or and from the remineralization processes producing CO2 constantly. RuBisCo uses CO2 . CO2 overproduction can be driven out before entering the display. Calcium and other minerals and building materials will be produced. Depending on the CO2 availability and consumption in the biofilm also carbonate may become available.
It is making a choice between active management using the biological processes which have to take place anyway or and adding more chemicals..

Calcium can be controlled by cultivating Halimeda in the biofilter. ref: https://www.baharini.eu/baharini/do...icatie#fotosynthese_geïnduceerde_calcificatie

 

[Randy Holmes-Farley]

Remineralization including nitrification takes place everywhere, on any substrate. These processes will rig up the balance anyway. Using a simple biofilter makes active nutrient management possible and the ideal substrate can be provided. pH will be buffered better as most acids will be used in the filter and the carbon source is retrieved from the calcium-carbonate substrate or and from the remineralization processes producing CO2 constantly. RuBisCo uses CO2 . CO2 overproduction can be driven out before entering the display. Calcium and other minerals and building materials will be produced. Depending on the CO2 availability and consumption in the biofilm also carbonate may become available.
It is making a choice between active management using the biological processes which have to take place anyway or and adding more chemicals..

Calcium can be controlled by cultivating Halimeda in the biofilter. ref: https://www.baharini.eu/baharini/doku.php?id=nl:makazi:chemie:calcificatie#fotosynthese_geïnduceerde_calcificatie

you are suggesting dealing with the rising calcium with a plant that precipitates calcium carbonate. So you just came full circle and depleted alkalinity again.

 

[blasterman]

For the billionth time calcium and alkalinity are not consumed at balanced ratios unless you have a very mature tank and a massive load of hard corals or clams. Alk is consumed in younger tanks via algae and bacteria colonies at an astonishing rate because its biological food. Calcium is consumed at a fraction the rate....unless you have lots of clams or big monitora caps or table acros. A half dozen small SPS frags in a big tank wont budge calcium levels over even months.

The clowns pushing balanced dosing on non SPS dominant tanks arent much better than robo callers selling you car warranties and I really wish Randy would take a stronger stand on this.

Keep your alk stable and slightly elevated on younger tanks. Put your calcium test kit away.

 

[Randy Holmes-Farley]

For the billionth time calcium and alkalinity are not consumed at balanced ratios unless you have a very mature tank and a massive load of hard corals or clams. Alk is consumed in younger tanks via algae and bacteria colonies at an astonishing rate because its biological food. Calcium is consumed at a fraction the rate....unless you have lots of clams or big monitora caps or table acros. A half dozen small SPS frags in a big tank wont budge calcium levels over even months.

The clowns pushing balanced dosing on non SPS dominant tanks arent much better than robo callers selling you car warranties and I really wish Randy would take a stronger stand on this.

Keep your alk stable and slightly elevated on younger tanks. Put your calcium test kit away.

Bacteria and algae do NOT Consume alkalinity, unless you mean the very few calcifying algae such as halimeda.

 

[Customtank]

I mainly dose alk these days. Manually dose mag. Keep it at 13000 and all is more stable.

 

[Belgian Anthias]

you are suggesting dealing with the rising calcium with a plant that precipitates calcium carbonate. So you just came full circle and depleted alkalinity again.

About Calcium and alkalinity. You obviously did not make the effort to read the article in reference.
One may manage the calcium content with a plant that precipitates calcium carbonate and it will not deplete alkalinity again! This plant precipitates calcium carbonate in private, not in public as do corals.
Coral calcification uses calcium and alkalinity and releases CO2 in the water column supporting algae growth in the near environment. Calcifying algae as Halimeda may use this CO2, it does not deplete alkalinity in the water column, it uses photosynthetic induced calcification, completely different from corals which use transcalcification, as shown in the reference added in the previous reaction. ref: https://www.baharini.eu/baharini/doku.php?id=nl:makazi:chemie:calcificatie

Bacteria and algae do NOT Consume alkalinity, unless you mean the very few calcifying algae such as halimeda.

Well, you know I do NOT agree. If ammonium is used as nitrogen source growing algae and bacteria deplete alkalinity , if nitrate is used as a nitrogen source for growth alkalinity is supported. Using algae in a refuge it is the intention to harvest it or feed it. The same for bacteria ( bio floc) and the use of a skimmer. Theoretically correct and proven in practice. ref: https://www.baharini.eu/baharini/doku.php?id=nl:makazi:het_water:ammonium_reductie We had the discussion before.
If someone measures alkalinity, the result includes the transition to ammonium. Compared to the possible alkalinity consumption and influence on pH by nitrification in the tank it is of no importance.
The use of a biofilter provides pH and alkalinity stability and easy nitrogen management, also in high nutrient systems

There are many marine algae out there having photosynthetic induced calcification but as they do not all have inter-utricular spaces where the precipitation takes place the result will be different. A lot of algae have special futures to prevent PIC.

Adding chemicals for pH and alkalinity corrections is often chock therapy. Active management of biological processes, the use of bio-filters, reduces or may prevent the need for chemicals and provides a more stable environment.

I suggest Calcium can be managed using Halimeda without depleting system alkalinity.

 

[Randy Holmes-Farley]

I’m not going to fight you every time trying to explain chemistry to you over and over and over.
It is impossible to form calcium carbonate without consuming alkalinity. The carbonate may be made from CO2, and many organisms do that, but that production must deplete alkalinity by consuming OH- or producing H+, or otherwise performing reactions that will deplete alkalinity.

 

[Randy Holmes-Farley]

This linked scientific article which can be read in full for free monitors calcification in various halimeda species under various conditions monitoring the drop in alkalinity:

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“Rates of calcification were determined with the alkalinity anomaly technique (Chisholm and Gattuso 1991).”

If you go to that reference, you can see that it is performed by measuring the drop in total alkalinity during calcification:

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