Sodium Bicarbonate

[remix8315544]

I need to raise my alkalinity level from 7 dKH to 8 dKH before I start dosing Kalkwasser. My calcium level is currently at 470 so no need to make adjustments there. PH level is 8.0 which I understand will go up to where I would like it at 8.2 to 8.3 once I start dosing the Kalk. My question, is there any difference in the Sodium Bicarbonate you buy from an Aquarium Supply store and Baking Soda you would buy at the Grocery Store ? Thanks.

 

[GTR]

Been using Arm and Hammer for years

 

[remix8315544]

Thanks. I couldn't see any difference but figured it was worth checking before I put it in the tank.

 

[dkeller_nc]

Been using Arm and Hammer for years

Yep, just as good as aquarium supplier Sodium Bicarb. Only caveat is to be sure that you get the A&M baking soda intended for food applications. Some of those yellow & orange boxes intended for odor neutralization have some additional ingredients.

 

[remix8315544]

Got it. Thanks.

 

[rfgonzo]

To answer your question, Yes, there is a difference $$$$.

 

[powderblue1]

I thought you had to cook the baking soda in the oven before its chemistry is the same as dKH buffers sold by Kent Marine and such.
I was under the impression that if you just add BS that is unbaked you have a greater chance of raising dKH levels to a point where magnesium levels are too greatly affected and not easily remedied by partial water changes alone know I read something about baking the baking soda first, just forgot because I buy the gallons of buffer that last a year (about 10-cents a day for two reef tanks combined) Of course all of this is dependent on amount of coraline and corals per unit of water as well. Just mt 2-cents Greetings Reef Central Community! Brand new to the forums and loving the interesting reads!

 

[bertoni]

[welcome]

If you bake the baking soda, it will be converted to washing soda (sodium carbonate), which will make a higher-pH supplement. Other than the pH effect, there's no real difference.

 

[tmz]

I thought you had to cook the baking soda in the oven before its chemistry is the same as dKH buffers sold by Kent Marine and such.
I was under the impression that if you just add BS that is unbaked you have a greater chance of raising dKH levels to a point where magnesium levels are too greatly affected and not easily remedied by partial water changes alone know I read something about baking the baking soda first, just forgot because I buy the gallons of buffer that last a year (about 10-cents a day for two reef tanks combined) Of course all of this is dependent on amount of coraline and corals per unit of water as well. Just mt 2-cents Greetings Reef Central Community! Brand new to the forums and loving the interesting reads!

Bicarbonate is HCO3; carbonate is CO3. Bicarboante has one unit of alkalinity, ie, it can neutralize one unit of acid H+. Carbonate has 2 units since it has no H+ . Baking bicarbonate drives of the H+. There is no effect on magnesium in either case. The same amount of baked baking soda will give you twice the alk that unbaked will give you not the other way around as stated.

 

[powderblue1]

Yes. Sorry about that. I guess I misspoke. I understand that removing the water will give you a stronger alk powder and a carbonate. I just thought that using straight BS was less stable. I do know that raising your alk too high can give you problems with magnesium levels though. Have seen the results and they can be hard to get a hold of. Thanks for the info! Since I have your ear, how much straight BS do you use per gallon of RO water at a pH of 6 (not sure of the alkalinity, I would guess low though given the pH) in order to make it decent top-off water for a reef tank with fish and soft corals?:fish2:

 

[bertoni]

A very high alkalinity level might cause calcium carbonate to precipitate, but it won't affect the magnesium level much.

The pH of RO/DI water is irrelevant. It has no buffering capacity, so it will conform to the pH of the tank. Buffering it might drive the alkalinity of the tank too high, as well.

 

[tmz]

I do know that raising your alk too high can give you problems with magnesium levels though. Have seen the results and they can be hard to get a hold of.

I don't know what you mean? More carbonate alkalinity results in more precipitation of calcium carbonate;magnesium coats nucleation sites where calcium carbonate has formed stopping the growth of the calcium carbonate crystal. Thus it allows more calcium carbonate to remain in solution, since precipitation of calcium carbonate is slowed when magnesium coats it. The effect on magnesium itself is related to the uptake of magnesium in calcium carbonate and by organisms. Higher alk in acceptable ranges doesn't cause a problem with magnesium levels in any significant way if at all.

This article may be of help:

http://www.advancedaquarist.com/issues/oct2003/chem.htm

This is from it:

"...This is the point that magnesium gets onto the growing surface of the crystal, essentially poisoning it for further precipitation of calcium carbonate. Since magnesium can reduce the likelihood or extent of calcium carbonate precipitation in this fashion, it thus acts to make it easier to maintain high levels of calcium and alkalinity...."

 

[powderblue1]

Hello gentlemen. First I will speak to Bertoni. A more basic solution will lower pH, however slightly that may be. You say "conform". If what you mean by that is go down then yes it will conform. My tank's CaCO3 levels hover around 100 - 110 ppm due to the number of corals in the system and extreme coraline cake. I have been dosing Calcium Carbonate in my RO water forever and it raises the pH as well as alk of the solution. If I put straight RO water from my source in the tank to replace the gallon of top-off I lose a day then I would be in trouble indeed.

Next, in reply to Tom, who does seem to know his stuff, but is a bit confused by my posts, I must say that I apologize again if you are not understanding me. The quote you pulled from that article is supporting what I am saying about high alk levels. Can you tell me what happens to the Mg once it gets into the growing surface? I'm not sure, but Mg levels might be less if it gets removed during calcification, and at the same time being absorbed by organisms. I think it is safe to say that levels over 200ppm is bad for a number of reasons. Thank you for your knowledge and literature.

Great site reefers. Thank you for your time and attention. What is your tanks CaCO3 at on a given Sunday? I wish I could keep mine higher, but I guess I will add some more buffer,, or now baked baking soda to my water change water and top-off water. I have to get a pic on for y'all. PEACE...

 

[bertoni]

A more basic solution will lower pH, however slightly that may be.

Not necessarily, actually, but in this case, the pH difference will be unmeasurable assuming that the water added is at carbon dioxide equilibrium with the tank. Otherwise, the pH might drop or rise a tiny bit temporarily. In any case, there's no need to buffer RO/DI used for topoff.

 

[tmz]

A more basic solution will lower pH, however slightly that may be.

Did you mean a more acidic solution?

 

[tmz]

Can you tell me what happens to the Mg once it gets into the growing surface? I'm not sure, but Mg levels might be less if it gets removed during calcification, and at the same time being absorbed by organisms

It is sunk in the crystal , likely for millennia unless the aragonite is dissolved.

However, the amount of magnesium as a proportion of aragonite is around 1% or so for most calcifying organisms ; any additional growth related to higher alk wouldn't cause a problem since it would be de minimis.

Say an additional 50 ppm ( ldkh ) of carbonate alkalinity related to increased uptake and growth is used from a maintained level of 250 ppm carbonate alkinity( 14 dkh) ,then about 6 ppm of calcium will go with it and only about 0 .5ppm magnesium from a baseline of 1300ppm or so; that's only 0.04% which is easily made up in a typical reef tank via water changes, food et alia.


The recommended levels for alkalinity are: 7 to 11ddh but that window is not framed by magnesium concerns, more about growth levels desired and nutrient availaibilityand pH.

 

[Buzz1329]

Bicarbonate is HCO3; carbonate is CO3. Bicarboante has one unit of alkalinity, ie, it can neutralize one unit of acid H+. Carbonate has 2 units since it has no H+ . Baking bicarbonate drives of the H+. There is no effect on magnesium in either case. The same amount of baked baking soda will give you twice the alk that unbaked will give you not the other way around as stated.

Any worthwhile article/thread you have at hand that details the baking process?

Thanks,

Mike

 

[bertoni]

This article describes the whole 2-part:

http://reefkeeping.com/issues/2006-02/rhf/index.php

Baking a thin layer for about an hour at 350 F or so should be fine, as described.

 

[powderblue1]

Yes. More acidic. Sorry Tom I love the info. I guess there is more to this hobby than meets the eye ey? silentium est aurum...

 

[tmz]

Silence may be golden but doesn't help learning and discussion. Ask away,that's what the forum is for.