High Alk consumption

Clownfishy

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I have recently setup a new aquarium but moved my old rock and corals into this new tank. After about a week, my alk consumption increased but not calcium. Each day I am currently dosing -
  • 20ml of Randys recipe (Backing Soda)
  • 6ml of Calcium Chloride
  • 3ml of Aquaforest mineral salts (was dosing 6ml inline with Calcium but lowered it as I am not sure what to align it with while alk and calcium dosing are not inline)
  • 0.3ml NOPOX
  • 200ml of kalk (at night)
My Aquarium is approx 88l (23.5 gallons) and parameters are -
  • Alk 8
  • Cal 445
  • Mag 1500 (cannot get this down. Tested with 2 different test kits)
  • Nitrate 10
  • Phosphate 0.2 (coming down now I am dosing NOPOX)
  • Potassium 440
  • Salinity 35.1
  • Temp 25c (77f)
I thought I read someone that the growth of bacteria can be a source of high alkalinity consumption so could it be that as this is a new tank and I am dosing NOPOX to increase the bacteria, that bacteria are consuming the alk? Or did I read that completely wrong and if so, why the difference when I have calibrated the dosing pump so it cannot be different calibration.

Many thanks for any help
 
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MnFish1

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I have recently setup a new aquarium but moved my old rock and corals into this new tank. After about a week, my alk consumption increased but not calcium. Each day I am currently dosing -
  • 20ml of Randys recipe (Backing Soda)
  • 6ml of Calcium Chloride
  • 3ml of Aquaforest mineral salts (was dosing 6ml inline with Calcium but lowered it as I am not sure what to align it with while alk and calcium dosing are not inline)
  • 0.3ml NOPOX
  • 200ml of kalk (at night)
My Aquarium is approx 88l (23.5 gallons) and parameters are -
  • Alk 8
  • Cal 445
  • Mag 1500 (cannot get this down. Tested with 2 different test kits)
  • Nitrate 10
  • Phosphate 0.2 (coming down now I am dosing NOPOX)
  • Potassium 440
  • Salinity 35.1
  • Temp 25c (77f)
I thought I read someone that the growth of bacteria can be a source of high alkalinity consumption so could it be that as this is a new tank and I am dosing NOPOX to increase the bacteria, that bacteria are consuming the alk? Or did I read that completely wrong and if so, why the difference when I have calibrated the dosing pump so it cannot be different calibration.

Many thanks for any help

Curious - what is your pH? And - how much has your alkalinity consumption increased (i.e. are you adding more, etc)? Though bacteria can produce acids, unless you're having a bacteria bloom, etc - that would be unlikely.

A couple other things to consider 1) are your tests (alkalinity) accurate (Doublechecked)?. 2) are you measuring alkalinity at the same time? 3). Your adding a lot of stuff with Ca and Alkalinity and have been changing some of those - so I might hold off on making other changes - except - that Aquaforest mineral salts (from what I read) contains Mg++.

Here is a quote from @Randy Holmes-Farley :
"Calcium Carbonate Mathematics

One of the interesting features of seawater is that there is a lot more calcium than there is alkalinity. By this I mean that if all of the calcium in seawater (410 ppm; 10.25 meq/L) were to be precipitated as calcium carbonate, it would use up a total alkalinity of 20.5 meq/L. In a less drastic scenario, let's say that calcium carbonate is formed from tank water starting with an alkalinity of 3 meq/L and that it is allowed to drop to 2 meq/L. How much has the calcium declined? It is surprising for many people to learn that the calcium would only drop by 20 ppm. Consequently, many aquarists observe that their calcium levels are relatively stable, but alkalinity can vary substantially. This is exactly what one would expect based on the fact that the tank already has an abundance of calcium."
 
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Clownfishy

Clownfishy

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Many thanks for the response. My pH is normally between 7.9 to 8.1. When I setup the tank, I was dosing approximately 5ml of both Calcium, Alkalinity and Aquaforest mineral salts. However, in that first week, I noticed my alk dropping but not my calcium so started testing alk daily. I slowly increased over the next couple of weeks and I am now at 20ppm. I have only increased my calcium 1ppm since starting the tank but I wonder 445-450ppm of calcium may be a little high.

I have not seen a bacteria bloom and considering the high fish load, the bacteria are holding up OK although I do have high phosphate which is why I am now dosing 0.3ml of NOPOX per day. I think I am going to end up around 0.5ml of NOPOX per day but I am being very careful and only slowly increasing the dosage so I do not bottom out my phosphates.

Very interesting what Randy wrote and thanks for posting that. I think I might let me calcium drop to around the 400 mark and see if this changes anything and if it brings down the high levels of magnesium. I am about to make up some fresh saltwater so I am going to test the new water. I switched to Fritz Pro Reef salt (blue box) when I setup this aquarium and have not tested the new salt so will post the results here.

I am worried my alk will drop through the floor if I stop dosing but I think it is leveling off at 20ppm so I will keep a very close on eye it. I am testing everything all the same time so there is no difference in the timing of the tests. Below are some the graphs of water parameters since the aquarium was setup on 6th November.


Thanks again for your response.

pH.png


Alk.png


Phosphate.png
 
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Clownfishy

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Results of my new Fritz salt after 1.5 hours of mixing at a temperature of 25c (77f) at 35ppt -

Alk 9.1
Cal 450
Mag 1395

MnFish1

Magnesium
Looks like you where right about the Aquaforest containing Magnesium as my aquarium is 1500 so the extra mag must be in the Aquaforest mineral salt. I have cut the Aquaforest mineral salt dosing in half and if that does not do the trick, I may actually stop dosing it as I am now down to just 2ml a day so not sure it is worth it as I perform a 20% water change each week.

Calcium
Looks like I will not be able to reduce my calcium much below 450 as the salt is around that and I do not like too much fluctuations during a water change.

Alkalinity
Looks like I will be dosing even more Soda Ash as there is a 1ppm difference to the new salt mix and my aquarium water so I am going to raise it from 8.1 to 9.1.

pH
I did not test the pH of the new saltwater however, it is clearly higher than 8 as I got a bit of a jump in the aquarium after the water change -
pH.png


I will report back in a few days and see if the alkalinity consumption reduces. If it has not, I may go back and mix another batch of soda ash as maybe the issue is in the mix itself and I am not dosing the concentration I think I am.
 
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Clownfishy

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Still no reduction in Alkalinity consumption and as I have decided to raise my alk levels to 9 to match the newly mixed salt mix, I am now dosing 22ml per day. My calcium chloride dosing is now down to 3.5ml per day with calcium being 445ppm. I have now stopped dosing the Aquaforest mineral salts until I can work out why the alk consumption is so high.
If there is no change by the weekend, I will recalibrate the doser (again) and make up a new batch of Soda Ash.

When mixing the alk part of @Randy Holmes-Farley 2 part, it mentioned mixing with 1 US gallon. Does this mean I need to leave room in a 1 gallon jug for the baking soda or that I need exactly 1 gallon of water and have a jug bigger than 1 gallon to allow for the baking soda?

As I am from the UK we use litres and I do not need a total of 1 gallon, I just want to check I have the conversation right -

1 US gallon = 3.785411784 litres so I am mixing approximately 198 grams of baking soda to 2 litres of RO/DI water.

Does that sound about right?
 
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MnFish1

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Still no reduction in Alkalinity consumption and as I have decided to raise my alk levels to 9 to match the newly mixed salt mix, I am now dosing 22ml per day. My calcium chloride dosing is now down to 3.5ml per day with calcium being 445ppm. I have now stopped dosing the Aquaforest mineral salts until I can work out why the alk consumption is so high.
If there is no change by the weekend, I will recalibrate the doser (again) and make up a new batch of Soda Ash.

When mixing the alk part of @Randy Holmes-Farley 2 part, it mentioned mixing with 1 US gallon. Does this mean I need to leave room in a 1 gallon jug for the baking soda or that I need exactly 1 gallon of water and have a jug bigger than 1 gallon to allow for the baking soda?

As I am from the UK we use litres and I do not need a total of 1 gallon, I just want to check I have the conversation right -

1 US gallon = 3.785411784 litres so I am mixing approximately 198 grams of baking soda to 2 litres of RO/DI water.

Does that sound about right?
IF You're using sodium bicarbonate - you need 302 gm x 3.78/4 = 285 grams for 4 liters.
If you're using sodium carbonate - you use 381 grams x 3.78/4 = 360 grams for 4 liters

Using the dosage of sodium bicarb/bicarbonate amounts in the BRS formula - which is I believe what @Randy Holmes-Farley 's solutions are based on - hopefully he will chime in!

EDIT - double check these numbers - it seems to me there your calculations might be off somehow - Randy has multiple recipes - and Its unclear which one you're using (to me)
 
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Clownfishy

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So I think I may have screwed up on the baking. Reading the above post by @MnFish1 and then going over this thread -
I had not quite realised that the amount you bake in one go has such a bearing on the mix. I am using the Recipe #1, Part 2: The Alkalinity Part
from here http://reefkeeping.com/issues/2006-02/rhf/index.php#1

Instead of just backing 594 grams as it clearly states -
"Spread baking soda (594 grams or about 2 ¼ cups) on a baking tray and heat in an ordinary oven at 300°F",
I have not payed attention to the amount I am baking and emptied a couple of boxes of Arm & Hammer onto the try and baked them for 1 hour. I cant even remember the size of the boxes so this is where I may have screwed up!

I then read Randy's post "You can only know the value if you baked it perfectly. Perfect baking of 594 g of NaHCO3 results in 375 grams of Na2CO3" and calculated -
375 / 3.7854 x 2 = 198.129 and mixed 198 grams of what I baked with 2 litres of water and this is what I am dosing.

If I have screwed up (which looks like I have!), is it OK to continue to dose what I have but just at much higher dosage than if had I baked the right amount?
 
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Clownfishy

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I have another question (possible a dumb one!). Could Arm & Hammer baking soda contain phosphate or inaccurate baking method of Arm & Hammer (please see my post above) cause the introduction of phosphate? I have quite high phosphate levels and I have put it down to my high load of fish however, because of the amount of Alkalinity I am dosing, I am finding my phosphate increase each time I raise the dosing amount.
 
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Clownfishy

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My alk consumption is now nearly back to normal so I was barking up the wrong tree thinking I had cooked it incorrectly (see my comments a couple of posts back)! Someone with far more knowledge can chip in if they would know if either of these statements maybe true as I cannot fathom why I burnt through so much alkalinity and then it went to normal
  1. Do new tanks burn through alkalinity establishing new bacteria?
  2. Does high phosphate have a bearing on alk consumption?
Although I could not say there is a correlation, I did notice my Alkalinity stabilize once I got to 9 and at the same time, my phosphate and nitrate started to drop due to higher NOPOX dosing -

NOPOX
1 - 2 ml per day (was 0.3ml)

Soda Ash
:4.5ml per day (was 20ml)

Calcium Chloride
3.5ml (was 6ml). I reduced my calcium a bit to match the newly made up salt water

Aqua Forest MIneral Salts
I have stopped dosing this as I my Magnesium is over 1500 and I am assuming it is from the Aquaforest Mineral salts as my newly made saltwater is mixing up with 1395 Magnesium.

Kalk
215ml per night (was 200)

I would really like to know why I would need to dose 4 times the alk level compared to calcium and was wondering if anyone else has experienced this?

Here is some further graphs and you can see Saturday was the turning point of having to reduce the Soda Ash dosing quickly (although I overshot my 9 goal).

Screenshot 2021-12-06 18.25.19.png


My Phosphate (drops same day)
Screenshot 2021-12-06 18.21.19.png


Comparison (red=phosphate, blue = alkalinity)
Screenshot 2021-12-06 18.48.41.png
 

Randy Holmes-Farley

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  1. Do new tanks burn through alkalinity establishing new bacteria?
  2. Does high phosphate have a bearing on alk consumption?

High phosphate, like high magnesium and high organics and low alk and pH and calcium all contribute to lower likelihood of precipitating calcium carbonate.

Increasing nitrate (like in a cycling new tank) depletes alkalinity.
 
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Clownfishy

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High phosphate, like high magnesium and high organics and low alk and pH and calcium all contribute to lower likelihood of precipitating calcium carbonate.

Increasing nitrate (like in a cycling new tank) depletes alkalinity.
Many thanks @Randy Holmes-Farley. I cannot say I have seen evidence of precipitation but could the precipitation be spread throughout so to make it unnoticeable rather than concentrated in one place?
 

Randy Holmes-Farley

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Many thanks @Randy Holmes-Farley. I cannot say I have seen evidence of precipitation but could the precipitation be spread throughout so to make it unnoticeable rather than concentrated in one place?
yes. It happens in most tanks to some extent.
 
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