Daily dosing for Kh

Scouter Steve

Active Member
Just a question here. I find my reef is using 3-4 teaspoons a day of baked baking soda. Could this be normal for a 325 gallon system with 350 pounds of LR and maybe 12 small SPS colonies? I do run a pair of phosban reactors and notice a Kh drop whenever I replace media. I am trying to maintain 9.6 dkh.
 

Boomer

Reef Sanctuary's Mr. Wizard
Steve, that is not much at all and is givng a daily avg. requirement/need/ consumption of 0.5 dKH / day . Some tanks are more than twice that amount.

And there is nothing wrong with using Baking Soda.
 

aquaticimports

Has been struck by the ban stick
Another consideration of KH is that you can generally safely add the buffers (both freshwater and saltwater) that effect KH without sudden changes in chemistry (unless your freshwater KH is under 50 ppm already), unlike a direct ph or GH change. Maintaining these KH buffers keeps your tanks pH form drastic swings which can be deadly.

Baking Soda (Sodium Bi-Carbonate HCO3-), is often used for KH, Sodium Bi-Carbonate will buffer at 8.0 to 8.2. Just a little Sodium Carbonate will absorb free H+ ions, and this causes alkalinity (which is the lack of H+ ions).
To stop the Sodium Carbonate ions from consuming too much H+ and to keep a pH of 7.0 we need to restrict the amount of Baking Soda used, as it is always looking for H+ ions to consume. This is why I prefer using products that not only contain sodium carbonates (or sodium bi carbonates), but the proper ratios of other minor elements such as Calcium and Magnesium. Sea Chem Buffer (Marine OR Freshwater) and to a lesser degree, aragonite and Mineral Blocks are examples.
Sea Chem Buffer can be safely used for raising kH (& pH) in freshwater as well or you can use Sea Chem Alkaline Buffer as both are preferable and safer than baking soda, especially in community aquariums where baking soda can change pH too quickly (also baking soda maintains a more stable KH). The added calcium and other elements keep a more stable KH/GH and add necessary trace and minor elements (of course, use in moderation in freshwater). This article will explain a little more about the need for other elements besides Baking Soda (HCO3): "Proper Osmotic Function; Electrolytes".
Wonder Shells are an excellent compliment for raising Calcium, magnesium, and electrolyte levels quickly when used with aragonite or even Baking Soda, however by themselves they do not raise KH much (they are great for Calcium and electrolytes though and for maintaining KH).

Sea Chem Buffers or similar products are better for pH/kH control in livebearer and African cichlids aquariums or a combination of Marine Buffer and Wonder Shells. Before I over promote Wonder Shells, these can aid in proper water management, but they are not a magic bullet in ANY aquarium for poor aquarium husbandry such as mulm build up under gravel or decorations.
Aragonite or crushed coral is sometimes employed for KH and GH stabilization, however aragonite and crushed coral (as with Wonder Shells) only stabilize KH and should not be used in place of a true KH buffer such as Sea Chem Alkaline Buffer .
I do not recommend aragonite for soft water or general aquaria.
Aragonite is good at stabilizing a higher kH of around 240 ppm or more, which is the minimum KH (alkalinity) needed for Marine Aquariums, but does not respond to changes rapidly enough at lower kH levels. Even in marine aquariums with aragonite, this may not always be enough to maintain a proper KH (alkalinity) level, especially in tanks high bio loads and without adequate water changes (even skimming can remove some elements).

In lower pH community tanks (6.8 to 7.4) KH buffers such as Sea Chem Alkaline Buffer are still important, however I like to counter these with natural lower pH “buffers” such as Almond Leaves , Peat, and/or Mango/Drift Wood. Buffering your freshwater aquarium is especially important if you have plants fed by CO2 which will raise pH during peak growth times, and there is scientific evidence that GH plays a role here as well; please see this article for more about this subject: “AQUARIUM PLANTS; see PROPER NUTRIENTS ”

Back to baking soda, this is an old stand by method based on the fact that baking soda does raise pH and kH, the problem is there is much new research to show that calcium, magnesium, electrolytes and Redox play a more important role in aquatic chemistry than just pH or basic kH alone (which is another reason good old fashioned water changes often help improve fish health). Unfortunately the aquatics hobby is full of aquarist (especially in forums or uninformed LFS) that regurgitate this old information without checking the facts. If Baking Soda is used, I recommend using Wonder Shells to added needed calcium and other important electrolytes.

If you have a very unstable KH level (drops rapidly), look into causes such as a large amount of decomposing organic material. The more organic break down (de-nitrification), the more acids produced. Some filters if not cleaned regularly can cause this; including canister, UGF, and Wet/Dry.

For a really informative (and scientific) article about the relation of KH (Buffers) and pH, please follow this link:
pH of buffer - Henderson-Hasselbalch equation


I did not write this altho I agree.
 

Woodstock

The Wand Geek was here. ;)
RS STAFF
Baking soda = sodium bicarbonate (recipe#2)

Baked baking soda = sodium carbonate (recipe#1) will increase PH

An Improved Do-it-Yourself Two-Part Calcium and Alkalinity Supplement System by Randy Holmes-Farley - Reefkeeping.com

Recipe #1 is for use in reef aquaria whose pH is normal to low. In practice, more reef aquarists end up choosing this recipe than Recipe #2. It will tend to raise pH due to its alkalinity part's elevated pH, as do most of the commercial two-part additives. The increase in pH depends on the aquarium's alkalinity and, of course, on how much is added. Adding on the order of 0.5 meq/L of alkalinity increases the pH by about 0.3 pH units immediately upon its addition (and even higher, locally, before it has a chance to mix throughout the aquarium).
If you are using limewater (kalkwasser) and the aquarium is at pH 8.4 or above, this recipe is not the best choice. Otherwise, it is likely to be a good option. It is twice as concentrated as Recipe #2, because the baking process makes the baking soda more soluble.

Recipe #1, Part 2: The Alkalinity Part
Spread baking soda (594 grams or about 2 ¼ cups) on a baking tray and heat in an ordinary oven at 300°F for one hour to drive off water and carbon dioxide. Overheating is not a problem, either with higher temperatures or longer times. Dissolve the residual solid in enough water to make 1 gallon total.

Recipe #2 is for use in reef aquaria whose pH is on the high side (above 8.3 or so). It will have a very small pH lowering effect when initially added. The pH drop achieved will depend on the aquarium's alkalinity and, of course, on how much is added. Adding on the order of 0.5 meq/L of alkalinity drops the pH by about 0.04 pH units immediately upon its addition.
If you are using limewater (kalkwasser) and the aquarium is at pH 8.4 or above, this recipe may be the best choice. It is half as concentrated as Recipe #1 because the raw baking soda is less soluble because it's unbaked.
 

aquaticimports

Has been struck by the ban stick
Here is another angle on this
I found this post:
Some time ago MDP told me that baking soda was not a good idea because of the anti caking agents in it. I am one of those people who will test the things I hear to make sure it is true (or else I am like the mom and dad in the movie "Time Bandits"). I promptly read the ingrdients on a box of Arm and Hammer Baking Soda. It listed Sodium BiCarbonate only. So I added it into my 20 gallon quarantine tank with a power head and a couple of pieces of base rock. The "Q" tank has been in operation for about a year and gets no light and regular changes of NSW. The ph rose slightly (the buffering capacity of the water was low since it was NSW) but the kicker was this: Within a week, the outbreak of cyanobacteria was jaw dropping. In 20 years of maintaining reef tanks, I had never experienced cyano. I had never used baking soda either. It appears that the FDA does not require Aluminum Silicate to be listed as an anti caking ingredient either because it is not considered an ingredient in food or it is chemically inert or not reactive. After doing a large water change with NSW, the pH went back to normal and the cyano went away. I have not seen it since. I realize this is anecdotal but it is also demonstrative.

I still use Baking Soda extensively though......as a nasty tasting antacid
 

Boomer

Reef Sanctuary's Mr. Wizard
Aqua

I did not write this altho I agree.

I do not how you can agree when most of that copy/paste is for FW and FW and SW are not the same thing. There are other serious issues also that you have about understanding kH, Buffers, Bicarbonate or Carbonate. For example; The ratio of Carbonate to Bicarbonate is a function of pH. It makes no difference how much of either you add, the pH will determine the % for each. If the pH was 8.3 you will have more of each at a higher Alk but the % of each will still be the same. Or from another angle if the pH was 8.3 and the Alk was 2.5 meq / l, vs a Alk at that same pH with a ALk of 4 meq / l the % of bicarb to carb will be the same. You can't change it, which means if 2 tanks, 10 tanks or 1,000 tanks have a pH of 8.3 and a Alk of 2.5 meq / l both tanks will have the same amount of CO2, Bicarb and Carb. If on the other hand the pH rose from that 9.3 to 8.4 then there will be a slight increasing in the carb. Most of the buffer in seawater is bicarbonate and on the order of 85 %

Here is what I mean graphically

350px-Bjerr.png


The reason behind the use of BS is it has the least effect on pH while increasing the ALk. If one needs a boost in both pH and Alk the ratios of BS to SA are used. And if one is looking more for a pH boost then SA ( Sodium Carbonate).

If you are interested in real articles then read these

The Relationship Between Alkalinity and pH.
Chemistry and the Aquarium


Advanced Aquarist's Online Magazine - Chemistry and the Aquarium: What is Alkalinity?


A Simplified Guide to the Relationship Between Calcium, Alkalinity, Magnesium and pH by Randy Holmes-Farley - Reefkeeping.com


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


Low pH: Causes and Cures by Randy Holmes-Farley - Reefkeeping.com


High pH: Causes and Cures by Randy Holmes-Farley - Reefkeeping.com


And make sure you read this......


Calcium Carbonate as a Supplement (Aragamight; Liquid Reactor)
Chemistry and the Aquarium
 

aquaticimports

Has been struck by the ban stick
Here is another angle on this
I found this post:
Some time ago MDP told me that baking soda was not a good idea because of the anti caking agents in it. I am one of those people who will test the things I hear to make sure it is true (or else I am like the mom and dad in the movie "Time Bandits"). I promptly read the ingrdients on a box of Arm and Hammer Baking Soda. It listed Sodium BiCarbonate only. So I added it into my 20 gallon quarantine tank with a power head and a couple of pieces of base rock. The "Q" tank has been in operation for about a year and gets no light and regular changes of NSW. The ph rose slightly (the buffering capacity of the water was low since it was NSW) but the kicker was this: Within a week, the outbreak of cyanobacteria was jaw dropping. In 20 years of maintaining reef tanks, I had never experienced cyano. I had never used baking soda either. It appears that the FDA does not require Aluminum Silicate to be listed as an anti caking ingredient either because it is not considered an ingredient in food or it is chemically inert or not reactive. After doing a large water change with NSW, the pH went back to normal and the cyano went away. I have not seen it since. I realize this is anecdotal but it is also demonstrative.

I still use Baking Soda extensively though......as a nasty tasting antacid

Hey I'm just trying to help .I fully under stand the coralation between PH and KH.I have always beleaved that the use baking soda for ph buffering is not a good idea cause you dont know totally what in it!Pioint in case what I high lighted.How many other compounds are not listed cause the FDA does not reguire it? I am not trying to cause an issue .

P.S. Thanks for the article links I've read them.They are great information.
 

Scouter Steve

Active Member
Thanks for all the info here. Now I have to do a bunch of reading! One day I might get this all straight! Definitely fun learning it though.
 

Boomer

Reef Sanctuary's Mr. Wizard
the use baking soda for ph buffering is not a good idea cause you don't know totally what in it!Pioint in case what I high lighted.How many other compounds are not listed cause the FDA does not reguire it? I am not trying to cause an issue .

Many salt mixes have anticaking agents, to include carrying and binding agents in them. Do you have an assay of your sodium carbonate and what is in it ? It is also no really 100 % pure. How do you know the buffers that you are using also do not have a anticaking agents ? And how do you know BS has Aluminum Silicate ? There is no such thing, 99.99 % of the time, that is 100% pure. Even ACS or even Ultra Pure Certified Sodium Bicarbonate can only get to 99.99 % pure. And a box of that equal to Arm & Hammer will cost you an arm and leg.

Aluminum Silicate

Has nothing to do with the growth of Cyanobacteria.

You said...........

Don't use baking soda


An that is an issue. If you said it is not a good idea or one should not use Washing Soda I would stand behind you :)

I am not trying to cause an issue .

It is more of a debate than issue.
 
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