# [Wet Thumb Forum]-Seachem AcidBuffer and ph/kh/CO2 chart



## imported_shalu (Feb 13, 2004)

I asked Seachem about their AcidBuffer's effect on PH/KH/CO2 relationship. Not that I want to use the buffers, but just curious.

Me:
"I have a question about using Acid and Alkaline buffer. I believe using Acid buffer together with alkaline buffer would invalidate the PH/KH/CO2 charts used to determine CO2 levels in a planted tank, because of the presence of acid in acid buffer. Am I correct in that assumption? Thanks"

Seachem:
"I don't think that using an acid would invalidate the charts. The Acid Buffer is consumed in the conversion and creation of CO2 from the carbonate alkalinity. Essentially the lifespan of the Acid Buffer is limited to a very short period of time depending on KH - minutes. So its use would not make the charts invalid.
"
Roger, your comments?


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## Roger Miller (Jun 19, 2004)

They're probably right. Acid Buffer contains bisulfate salts. SeaChem doesn't print what kind of bisulfate salt. Simple bisulfate salts dissolve in water to give half-strength sulfuric acid. Sulfuric acid will destroy KH by reacting with bicarbonate to produce CO2. After an addition of Acid Buffer the pH will drop, then rebound as the extra CO2 escapes. The sulfuric acid is neutralized and won't effect the pH/KH/CO2 relationship.

This brings two things to mind:

1) the product seems misnamed. Acid Buffer doesn't act as a buffer in the pH range that will support life. It is just a strong acid.

2) combining Seachem's Acid and Alkaline buffers as they describe seems pointless. It should just give the same effect as using a smaller amount of either the acid buffer or the alkaline buffer alone.

A quick google search produced nothing about pink-colored bisulfate salts. I have to suspect that the color of Seachem's acid buffer may be from a dye. That isn't necessarily a bad thing. Bisulfate salts are acidic and corrosive. The pink color means you won't mistake it for something benign like table salt or sugar.


Roger Miller


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## imported_shalu (Feb 13, 2004)

> This brings two things to mind:
> 
> 1) the product seems misnamed. Acid Buffer doesn't act as a buffer in the pH range that will support life. It is just a strong acid.
> 
> ...


That's what I have been thinking after reading their response. If the reaction is over in a few minutes, all you get is temporary ph drop which disappears when CO2 escapes. Thanks for the analysis.


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## Margolis (Sep 22, 2004)

> Originally posted by Roger Miller:
> 
> 2) combining Seachem's Acid and Alkaline buffers as they describe seems pointless.


exactly. I have found that an airstone will bring the ph back up to normal in a matter of minutes, even when a lot is used. I do notice all the fine bubbles the acid buffer produces though. presumably co2, but I don't know.



> A quick google search produced nothing about pink-colored bisulfate salts. I have to suspect that the color of Seachem's acid buffer may be from a dye.


hmmm, my seachem acid buffer is snow white. Much whiter than any salt or sugar I have seen.

And it suffers from static cling like nothing I have ever seen. It clings to the sides of bottle and even jumps to the plastic bucket from the spoon if I get the spoon to close to the bucket..


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## Roger Miller (Jun 19, 2004)

> hmmm, my seachem acid buffer is snow white. Much whiter than any salt or sugar I have seen.


Mine is bright pink. The bottle is a few years old -- a gift that I've never had a use for. The label information is consistent with the MSDS provided by SeaChem, so I suspect that the product is the same in any significant way.

Roger Miller


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## Drone82 (Mar 4, 2005)

> Originally posted by Roger Miller:
> 2) combining Seachem's Acid and Alkaline buffers as they describe seems pointless. It should just give the same effect as using a smaller amount of either the acid buffer or the alkaline buffer alone.
> 
> A quick google search produced nothing about pink-colored bisulfate salts. I have to suspect that the color of Seachem's acid buffer may be from a dye. That isn't necessarily a bad thing. Bisulfate salts are acidic and corrosive. The pink color means you won't mistake it for something benign like table salt or sugar.
> ...


The pink color was a dye - Seachem no longer uses it (their Acid Buffer is white).

In regard to the #2 question... the combining of both products is intended when preparing RO/DI water. I did ask them this very question, here is what they said:



> If you were to add only Alk Buffer the pH would be sky high for most
> FW systems. The Acid Buffer acts as a balance to the high pH of the
> Alk Buffer. It doesn't convert all of the Alk Buffer and does not do
> so immediately anyhow. Both products are best used together.


Again this is when preparing RO water. The thing is, if you are doing CO2 injection... then the CO2 is basically your acid buffer. Anyhow, I follow their directions and ratios when preparing RO water change water.


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## Roger Miller (Jun 19, 2004)

> Originally posted by Drone82:
> 
> 
> 
> ...


and earlier in this thread



> Originally posted by Shalu:
> 
> 
> 
> > quote:The Acid Buffer is consumed in the conversion and creation of CO2 from the carbonate alkalinity. Essentially the lifespan of the Acid Buffer is limited to a very short period of time depending on KH - minutes.


And both of these quotes are from Seachem support? I guess there is some difference between "immediately" and "minutes" but I'm not sure that in this case it's very important.

Alkaline Buffer is baking soda. Acid Buffer is a bisulfate salt -- I'll guess sodium bisulfate, but potassium bisulfate seems fairly common too.

If you add Alkaline Buffer to RO/DI or distilled water you get solution that contains sodium and bicarbonate with a pH probably 8+. If you add Acid Buffer to that then the acid reacts (within minutes -- probably within seconds if it's well mixed) so that your solution now contains sodium, sulfate, bicarb and CO2 and the pH is lower. The CO2 escapes, the pH goes back up to about where it was, the salinity is higher and you have less buffer capacity than you started with.

What's more, your end product isn't really much closer to a well-reconstituted composition than it would be if you used no Acid Buffer at all. You still need to add calcium, magnesium, potassium (probably) and chloride before you have something like natural water.

I don't see that Acid Buffer contributes much to the effort.

Roger Miller


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## Margolis (Sep 22, 2004)

> Originally posted by Drone82:
> 
> 
> 
> ...


they seem to lie. Like roger said, acid buffer is not a "buffer". It creates and immediate drop in ph that will evaporate an return to what it was almost just as quickly. And I haven't noticed any sky high ph from using alkaline buffer. It seems to be nothing more than sodium bicarbonate. Baking soda used in the exact same amounts as alkaline buffer yield exactly the same kh and ph readings. So do yourself a favor and stop using the acid buffer and alkaline buffer and switch to baking soda, it is much cheaper.

The only thing the acid buffer is useful for is to temporarily lower the ph of the water if you want the ph of the new water you are going to add to the tank to match that of your co2 ph controlled tank water when doing a water change.


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## Drone82 (Mar 4, 2005)

> Originally posted by Margolis:
> 
> So do yourself a favor and stop using the acid buffer and alkaline buffer and switch to baking soda, it is much cheaper.


It clouds the water. Alkaline Buffer does not. It also contains some impurities. Alkaline buffer is more refined. One container of Alkaline Buffer lasts me 1-2 years.

That's quite a bold stance you take. Seachem is quite a respected company... in fact they are in the process of moving to a new and bigger headquarters. If they are lieing about their products, you are basically saying they are breaking the law. Perhaps the FTC should be informed?


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## imported_shalu (Feb 13, 2004)

pure baking soda does not cloud water, countless people use it in aquariums. It's your money, if it gives you more peace of mind thinking the buffer is "purer", so be it, but remember baking soda is for human consumption.


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## snailman (Mar 8, 2005)

Tap water is also for human consumption, but you would not catch many fish keepers using tap water straight from the tap without any prior treatment with a dechlorinator. Something that is safe for human consumption does not mean it is safe for fish, our physiology and the processes behind it work differently to fish.


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## skids (Mar 23, 2004)

I use acid or discus buffer and alkaline buffer together in a non Co2 tank to maintain ph 6.2 to 6.5. Without going into why I want to target that pH, let me just add that the trouble with buffering complex solutions at certain pH's is that there are really only 10-15 good buffers available from suppliers that have useful pKa's . The range of pKa's is quite lumpy. Hence the simplest thing to do to make 0.1 pH adjustments is to mix an acid and a base and move it where you want. It is a favorite trick of bench chemists to mix two in a preset ratio to avoid spending 10 minutes adding glacial acetic acid or 10N NaOH dropwise and waiting with a pH meter to get the target. Again not really something you can sell over the counter, let alone ship interstate.

The Merck index has several charts to indicate how much Tris HCl and Trisma base powered to add to 1 liter to get your target with a minimum of fussing and measuring with a meter. Since many hobbyists would rather watch fish, and lack the gallon jugs of concentrated acid and base and a meter to mess around with stuff, I applaud Greg and the Seachem guys for providing a quick chart of how to mix two together. It is especially hand when I am doing 4 tanks and don’t want to take too long guessing and would rather change 15 gal and add 2 things and get onto the next one. 

I used to do lots of enzymology at a range of pH’s and had to make up lots of solutions from pH 4 to 11 in increments of 0.2. Believe me, I can do it but I am got tired of messing with it. Most of the buffers I used to target certain ranges are likely toxic to fish such as maleate, succinate and tris not to mention they are expensive. 

Without busting out the Merck index and looking up the pKa’s and estimating the buffering capacity of each, I would say they did the most common thing which is take two buffers, add them together and get a dual buffer system to have a better buffering capacity over a broader range.

I do have a slight gripe, which is that all the Seachem products are geared toward people with hard water and purposely precipitate the Ca and Mg. Our city water is soft and I would rather leave them in. When I use it, it precipitates so much I end up with kH 3 and gH 0. Yes 0. Not really what we want for vibrant plants. It’s great for Cardinal tetra but the java ferns keep disintegrating.


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## Roger Miller (Jun 19, 2004)

It's relatively simple to use bicarbonate as the base and CO2 as the acid. The bicarbonate is already in the water and many of us don't need to adjust it at all. Adding CO2 to planted tanks not only supplies the acid side of the buffer but it has a pleasant effect on plant growth and can be closely and automatically regulated with readily available equipment.

Since you have worked with enzymes over a range of pH I have a question for you. I read that the activity of many enzymes peaks at an alkaline pH and is much lower under neutral and acid conditions. Is that true? Do you suppose that variation in enzyme activity could cause lower algae growth at lower pH?


Roger Miller


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## skids (Mar 23, 2004)

Depends on the enzyme. You can sort of guess by figuring out the normal operating range of the tissue or animal. Most mammalian enzymes have activity peaks near pH 6.8 – 7.2 (blood) . Move too far away and the active site amino acids like histidine, glutamate, aspartate, tyrosine and lysine are not in their normal protonation and their physiological acid and base properties are altered. Generally 1 pH unit is 1 log activity difference when near it’s pKa but that goes to near nothing as you go two units away (think titration curve that is 4 pH units wide with flat ends.) Temperature is even more effective as are certain metal cofactors. 

Pepsin , the protease is added to laundry detergent and works best at slightly acid conditions, I think lots of companies slightly acidify detergent to increase it’s “stain fighting “ power. Algae and other plant enzymes work the same way. Mitochondria and vacuoles (which store starch and enzymes) and choroplasts (which do the photosynthesis) have specialized enzymes within their inner membrane surfaces which work optimally at pH 5-6 to work in pumping protons as a normal part of making ATP (in animal cells) or making ATP and NADPH in plants. 

Certain molds and fungi are adapted to acidic environments ( and their enzymes) because neighboring molds secrete acids as a normal waste product but also in defense. Generally those that need to digest the substrate (think rotting wood) are in this group.

I think you can use this trick to effect algae growth but I suspect for every species you suppress slightly, another will be unaffected or even promoted, so maybe you would just change the dominant species. Tom Barr can weigh in on this specifically. 

I think the most interesting “enzymatic” control would be using inhibitors like erythromycin which specifically bind and inhibit the protein translation ribosomes of the algae while leaving the tank bacteria and fish unaffected. I bet there are many more useful antibiotics available than we use in the hobby. Tom is working on some really cool ultrasonic techniques to disrupt algae cells while leaving plant and fish in rivers unaffected. His research has already been effective for one species and if he develops it further, I suspect we will all be buying ultrasonicator probes for tanks to clean up algae outbreaks some day. Basically specific frequencies can punch holes in algae ( and plant ) cell walls and then they lyse as water rushes in. He is dong it for noxious weed control, but it may be applicable to home use if it doesn’t make standing waves that crack glass or splash out the water.


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