New tank 3months - kH consumption

[lifeofalf]

Hey!
So I have a question about kH consumption in a fairly new tank. You can see my numbers below. Struggling with zero phosphate.
It’s stocked with 4 small torch/hammer drags in total.
I feel like the consumption of more than 1dkH every day is maybe too much? Can it be that the coralline algae started to grow without me seeing it? It’s ceramic rock.

I dose Tropic Marine All for reef based on the dkH number from the Reef Factory kH keeper plus.
It’s a innovative marine 20G.

Currently got bio balls and searched purigen in the back chambers. I also got a nano skimmer but I turned that off after seeing zero phosphate.

Thanks

 

[lifeofalf]

Btw. I also lost one of the torch frags..

 

[Randy Holmes-Farley]

Can you clarify how you determined that you are adding close to 1 dKH per day?

 

[Aaron75]

Following along because I'm having similar issues, if not more extreme. I haven't started dosing anything yet but I struggle to keep alk above 6 using weekly water changes. Tank is around 8 months.

 

[Randy Holmes-Farley]

Following along because I'm having similar issues, if not more extreme. I haven't started dosing anything yet but I struggle to keep alk above 6 using weekly water changes. Tank is around 8 months.

Abiotic precipitation of calcium carbonate and rising nitrate levels both serve to consume alkalinity.

 

[Aaron75]

Abiotic precipitation of calcium carbonate and rising nitrate levels both serve to consume alkalinity.

In english? Lol are you saying running high nitrate causes low alk? I keep nitrates steady at 15.

 

[Randy Holmes-Farley]

In english? Lol are you saying running high nitrate causes low alk? I keep nitrates steady at 15.

The production of nitrate consumes alkalinity. The consumption of nitrate adds the exact same amount of alkalinity.

if nitrate it stable at any level, alk is unchanging due to that process. However, if it is rising, alk is beign depleted.

Here's a copy and paste:

Alkalinity Decline in the Nitrogen Cycle

One of the best known chemical cycles in aquaria is the nitrogen cycle. In it, ammonia excreted by fish and other organisms is converted into nitrate. This conversion produces acid, H+ (or uses alkalinity depending on how one chooses to look at it), as shown in equation 1:

(1) NH3 + 2O2 --> NO3- + H+ + H2O
For each ammonia molecule converted into nitrate, one hydrogen ion (H+) is produced. If nitrate is allowed to accumulate to 50 ppm, the addition of this acid will deplete 0.8 meq/L (2.3 dKH) of alkalinity.

However, the news is not all bad. When this nitrate proceeds further along the nitrogen cycle, depleted alkalinity is returned in exactly the amount lost. For example, if the nitrate is allowed to be converted into N2 in a sand bed, one of the products is bicarbonate, as shown in equation 2 (below) for the breakdown of glucose and nitrate under typical anoxic conditions as might happen in a deep sand bed:

(2) 4NO3- + 5/6 C6H12O6 (glucose) + 4H2O --> 2 N2 + 7H2O + 4HCO3- + CO2

In equation 2 we see that exactly one bicarbonate ion is produced for each nitrate ion consumed. Consequently, the alkalinity gain is 0.8 meq/L (2.3 dKH) for every 50 ppm of nitrate consumed.

Likewise, equation 3 (below) shows the uptake of nitrate and CO2 into macroalgae to form typical organic molecules:

(3) 122 CO2 + 122 H2O + 16 NO3- --> C106H260O106N16 + 138 O2 + 16 HCO3-

Again, one bicarbonate ion is produced for each nitrate ion consumed.

It turns out that as long as the nitrate concentration is stable, regardless of its actual value, there is no ongoing net depletion of alkalinity. Of course, alkalinity was depleted to reach that value, but once it stabilizes, there is no continuing alkalinity depletion because the export processes described above are exactly balancing the depletion from nitrification (the conversion of ammonia to nitrate).

There are, however, circumstances where the alkalinity is lost in the conversion of ammonia to nitrate, and is never returned. The most likely scenario to be important in reef aquaria is when nitrate is removed through water changes. In that case, each water change takes out some nitrate, and if the system produces nitrate to get back to some stable level, the alkalinity again becomes depleted.

If, for example, nitrate averages 50 ppm at each water change, then over the course of a year with 10 water changes of 20% each, the alkalinity will be depleted by 1.6 meq/L (4.5 dKH) over the course of that entire time period. This process is one of the primary reasons that fish-only aquaria that often export nitrate in water changes need occasional buffer additions to replace that depleted alkalinity.

While the magnitude of the depletion described in the paragraph above is fairly easy to understand, it also can be converted into units that clarify the imbalance. The impact of alkalinity depletion on the calcium and alkalinity demand balance depends, of course, on the amount of calcium and alkalinity added (and consumed) over the course of that same year.

For a typical reef aquarium (assuming a daily addition of saturated limewater equal to 2% of the tank's volume), the amount of alkalinity added during the course of a year is 297.8 meq/L. Likewise, the amount of calcium added is 5,957 ppm Ca++, given the ratio of 1 meq/L of alkalinity for every 20 ppm of calcium that has been discussed above. If that 1.6 meq/L of alkalinity is added to create a larger demand of 299.4 meq/L over the course of a year, the new ratio for the total demand becomes 19.90 ppm Ca++ per 1 meq/L of alkalinity. Consequently, while this effect of nitrate production on alkalinity is enough to be noticed over the course of a year, it is substantially smaller than the other effects discussed in this article, and is unimportant for aquaria that maintain low nitrate levels.

 

[lifeofalf]

Can you clarify how you determined that you are adding close to 1 dKH per day?

Thanks for the reply.
Consuming more than 1dKH per day, therefore I dose quite a lot of Tropic Marine All for Reef (approx 12-14ml). So you can say that I'm adding (increasing) the dKH by more than 1dKH a day since I try to keep it stable.

 

[lifeofalf]

Can it be that it's still a new tank? Should I just keep up with 10-15% weekly water changes?

 

[Randy Holmes-Farley]

Not that is impacting the demand necessarily, but how you you using a dosing system with AFR that does not show up as alk when first dosed?

 

[lifeofalf]

Not sure what you mean here?
I measure alk with KH Keeper Plus and then I dose based on that reading. Then I measure again in 6hours and dose again. And so on. 4 times a day.

 

[Randy Holmes-Farley]

Not sure what you mean here?
I measure alk with KH Keeper Plus and then I dose based on that reading. Then I measure again in 6hours and dose again. And so on. 4 times a day.

This probably works out over time (but definitely do not start dosing this way). It is not nearly so simple as if you were dosing detectable alkalinity such as using carbonate. The KH Keeper cannot detect the alk that is in AFR until it is metabolized by bacteria. If there is a substantial lag before it is detectable, you may dose up the concentration of formate higher than necessary.

That said, over a few weeks it should stabilize and be OK.

In a new system, abiotic precipitation may be the biggest part of the alk demand. Low phosphate will also encourage that.

 

[lifeofalf]

Ok. Totally makes sense. Thank you so much!

 

[Aaron75]

The production of nitrate consumes alkalinity. The consumption of nitrate adds the exact same amount of alkalinity.

if nitrate it stable at any level, alk is unchanging due to that process. However, if it is rising, alk is beign depleted.

Here's a copy and paste:

Alkalinity Decline in the Nitrogen Cycle

One of the best known chemical cycles in aquaria is the nitrogen cycle. In it, ammonia excreted by fish and other organisms is converted into nitrate. This conversion produces acid, H+ (or uses alkalinity depending on how one chooses to look at it), as shown in equation 1:

(1) NH3 + 2O2 --> NO3- + H+ + H2O
For each ammonia molecule converted into nitrate, one hydrogen ion (H+) is produced. If nitrate is allowed to accumulate to 50 ppm, the addition of this acid will deplete 0.8 meq/L (2.3 dKH) of alkalinity.

However, the news is not all bad. When this nitrate proceeds further along the nitrogen cycle, depleted alkalinity is returned in exactly the amount lost. For example, if the nitrate is allowed to be converted into N2 in a sand bed, one of the products is bicarbonate, as shown in equation 2 (below) for the breakdown of glucose and nitrate under typical anoxic conditions as might happen in a deep sand bed:

(2) 4NO3- + 5/6 C6H12O6 (glucose) + 4H2O --> 2 N2 + 7H2O + 4HCO3- + CO2

In equation 2 we see that exactly one bicarbonate ion is produced for each nitrate ion consumed. Consequently, the alkalinity gain is 0.8 meq/L (2.3 dKH) for every 50 ppm of nitrate consumed.

Likewise, equation 3 (below) shows the uptake of nitrate and CO2 into macroalgae to form typical organic molecules:

(3) 122 CO2 + 122 H2O + 16 NO3- --> C106H260O106N16 + 138 O2 + 16 HCO3-

Again, one bicarbonate ion is produced for each nitrate ion consumed.

It turns out that as long as the nitrate concentration is stable, regardless of its actual value, there is no ongoing net depletion of alkalinity. Of course, alkalinity was depleted to reach that value, but once it stabilizes, there is no continuing alkalinity depletion because the export processes described above are exactly balancing the depletion from nitrification (the conversion of ammonia to nitrate).

There are, however, circumstances where the alkalinity is lost in the conversion of ammonia to nitrate, and is never returned. The most likely scenario to be important in reef aquaria is when nitrate is removed through water changes. In that case, each water change takes out some nitrate, and if the system produces nitrate to get back to some stable level, the alkalinity again becomes depleted.

If, for example, nitrate averages 50 ppm at each water change, then over the course of a year with 10 water changes of 20% each, the alkalinity will be depleted by 1.6 meq/L (4.5 dKH) over the course of that entire time period. This process is one of the primary reasons that fish-only aquaria that often export nitrate in water changes need occasional buffer additions to replace that depleted alkalinity.

While the magnitude of the depletion described in the paragraph above is fairly easy to understand, it also can be converted into units that clarify the imbalance. The impact of alkalinity depletion on the calcium and alkalinity demand balance depends, of course, on the amount of calcium and alkalinity added (and consumed) over the course of that same year.

For a typical reef aquarium (assuming a daily addition of saturated limewater equal to 2% of the tank's volume), the amount of alkalinity added during the course of a year is 297.8 meq/L. Likewise, the amount of calcium added is 5,957 ppm Ca++, given the ratio of 1 meq/L of alkalinity for every 20 ppm of calcium that has been discussed above. If that 1.6 meq/L of alkalinity is added to create a larger demand of 299.4 meq/L over the course of a year, the new ratio for the total demand becomes 19.90 ppm Ca++ per 1 meq/L of alkalinity. Consequently, while this effect of nitrate production on alkalinity is enough to be noticed over the course of a year, it is substantially smaller than the other effects discussed in this article, and is unimportant for aquaria that maintain low nitrate levels.

Wow, this is fun. This is why i love the hobby. So my nitrates are at 15, but without intervention, it's consumed and lowers to say.. 10 in 2 weeks. So that consumption of 5 nitrates/2 weeks actually raises my Alk? I'm only hurting the process by doing water changes? How does dosing Nitrates via Neonitro effect this exchange? Nitrates in=temporary alk lowering to then slight Alk raise?

 

[Randy Holmes-Farley]

Wow, this is fun. This is why i love the hobby. So my nitrates are at 15, but without intervention, it's consumed and lowers to say.. 10 in 2 weeks. So that consumption of 5 nitrates/2 weeks actually raises my Alk? I'm only hurting the process by doing water changes? How does dosing Nitrates via Neonitro effect this exchange? Nitrates in=temporary alk lowering to then slight Alk raise?

Dosing nitrate will raise alk over time, assuming the nitrate is being consumed.

Consumption from 15 to 10 ppm causes a 0.2 dKH boost to alk, so that effect is pretty small.