Stabilizing your tank pH with sodium bicarbonate (baking soda)

[dnalex 13,633]

The carbonate/bicarbonate system is one of the best biological buffers of pH, and is often used in aquaria to boost the alkalinity of systems (raising kH values). There is ready source of bicarbonate that aquarists can take advantage of, and that is baking soda (pure sodium bicarbonate).

There are several advantages to using baking soda as a buffer:

1. Cheap. I bought 12 pounds of baking soda for less than $7, while a 10.6 ounce bottle of Gold Buffer costs almost $14!
2. Easily available. Just go to any supermarket.
3. Works!
4. Doesn't affect the pH much. NOTE: All buffers will change your pH. Some will do so a lot, some a little. Baking soda won't change the pH that much, at the amounts you use. Keep in mind though, that if your pH is less than 7, it will bring it up to around 7.4-7.8.
5. We know exactly how much baking soda to add to raise kH by a certain amount. This is an extremely important, as it takes out the guesswork.

Disadvantages:
1. You have to keep adding with each water change, as opposed to crushed coral, for example.
2. It only raises kH, but does not raise gH, unlike crushed coral and some other buffer, for example.
3. This is critical. If you opt to use baking soda, you should take care to do a 100% WC in your tank every 2-3 months to avoid accumulation of too much sodium in the tank.

So, how much baking soda to add? I've made two tables (one in grams, the other in teaspoons) for your convenience.
Keep in mind that for goldfish and for optimal maintenance of beneficial bacteria, we want the kH to be around 100-150ppm. The same gH is ideal.



This post has been promoted to an article

[tithra 4,917]

awesome!! thank you Alex!

[Chai 7,337]

I've been curious about this ever since I saw you and another member discuss it in their thread. Super useful, thank you so much for the charts, too!!

Edited May 16, 2013 by Chai

[Mernany 3,708]

So did I ever tell you you're brilliant Mr. Robot? This is great information and helps when you have a pH crash like I did after cycling my first tank! Nice job!

[tassiegold 11]

Great info...thanks Alex.

Do you know it takes 5 times more baking soda to go from 100 - 110ppm in you add with teaspoons? Cheers

Edited May 16, 2013 by tassiegold

[yafashelli 9,540]

This is such a great idea. Thank you, Alex. The information is excellent.

[dnalex 13,633]

Great info...thanks Alex.

Do you know it takes 5 times more baking soda to go from 100 - 110ppm in you add with teaspoons? Cheers

Thank you.

No, I did not know. My understanding is that the increase should be relatively linear, with increase 10 mg/L requiring 53 grams of baking soda for every 1000 gallons.

[Helen 8,511]

YAY!!

[Goldsguy 267]

Awesome tables Alex. Could you discuss the advantages and disadvantages of baking soda versus gold buffer? My main question does gold buffer also raise gH and raise pH much? Would 100% PWC still be necessary?

[dnalex 13,633]

Awesome tables Alex. Could you discuss the advantages and disadvantages of baking soda versus gold buffer? My main question does gold buffer also raise gH and raise pH much? Would 100% PWC still be necessary?

Hello,

These are great questions. I've looked at the MSDS for the Seachem Gold Buffer many times, and all it says is that it's a proprietary blend of non-phosphate bicarbonate salts. So, it works exactly the same way as baking soda. How much of the Seachem Gold Buffer is sodium bicarbonate (baking soda), I am not sure, but I think that there will be some in there. So yes, every once in a while, I think it's still a good idea to do a 100% WC when you are using Gold Buffer. Having said that, I have to tell you that I am a big advocate of doing 100% WC every once in a while anyway, so that any sort of accumulated waste or unwanted products can be gotten rid of entirely.

Gold Buffer is designed to be stabilizing the pH around 7.8. In my experience, sometimes this can go up to 8.2. I think that you will find the same to be true for baking soda.

Gold Buffer most definitely will raise the kH. By how much should be very similar to the table I've posted above for baking soda.

To be honest, I cannot really think of any advantage the Gold Buffer may have over baking soda. They both work in the same way, using the bicarbonate buffering system. The Gold Buffer may raise your gH also by a little bit, but I do not know how much. So, after a few years of being a Gold Buffer fan, I am now almost through with my 4kg bucket, and will be transferring over to using baking soda exclusively.

[ashlee18 1,169]

I am confused. I always though baking soda wasn't considered suitable for maintaining pH but only raising it. That is just what I had always been told but with no explaination.

[dnalex 13,633]

I am confused. I always though baking soda wasn't considered suitable for maintaining pH but only raising it. That is just what I had always been told but with no explaination.

Whomever said that must be confused, unfortunately, and passed on incorrect information to you.

Baking soda is 100% sodium bicarbonate, which will work as a pretty good buffer, although things like crushed coral, which is calcium carbonate, will work better, since carbonates are better than bicarbonates at buffering.

All buffers will alter the pH to a certain extent, although baking soda should do that much less compared to some others.

[ashlee18 1,169]

It was just the key part was maintaining it. Just that you had to be careful about the pH dipping again.

[dnalex 13,633]

It was just the key part was maintaining it. Just that you had to be careful about the pH dipping again.

These bicarbonate buffers work exactly the same way as baking soda (100% sodium bicarbonate). So, if you add enough to raise the kH to the appropriate level (100-150ppm), this should not be a concern.

If it is, then it will be a concern for the buffer as well, since bicarbonate ions are carbonate ions.

I wish they had given you reasons for why they think that baking soda shouldn't be used.

[Narny105 1,992]

Yay bicarb :D

Great article, Alex I gave up on buying seachem gold buffer when it went up to $25 a 500ml bottle, which probably lasted me 3-4 weeks in my current tank... Bi carb is a few bucks for twice as much!

Edited May 16, 2013 by Narny105

[Flipper 13,057]

This is fascinating and very helpful. If crushed coral is better, do you put it in filter or as substrate? Thanks Alex for the charts.

[dnalex 13,633]

This is fascinating and very helpful. If crushed coral is better, do you put it in filter or as substrate? Thanks Alex for the charts.

You can do either, to fit whatever suits you.

You should know that while crushed coral is better, the rate at which it dissolves might not be fast enough for your system, unless you add a lot.

[Flipper 13,057]

This is fascinating and very helpful. If crushed coral is better, do you put it in filter or as substrate? Thanks Alex for the charts.

You can do either, to fit whatever suits you.

You should know that while crushed coral is better, the rate at which it dissolves might not be fast enough for your system, unless you add a lot.

Good to know. Thanks again.

[Sovandareal 9]

great information Alex! well my pH has been between 7.8-8 ppm every time i test it. does that mean my water is hard or soft? i just ordered a test for kH and Gh now and it should come by tuesday.

[dnalex 13,633]

great information Alex! well my pH has been between 7.8-8 ppm every time i test it. does that mean my water is hard or soft? i just ordered a test for kH and Gh now and it should come by tuesday.

We'll know more when you test for it. It appears that your pH is relatively stable though.

[ElaineSelene 39]

What about lowering PH with vinegar or similar? Can anyone tell me about that?

[dnalex 13,633]

What about lowering PH with vinegar or similar? Can anyone tell me about that?

The goal is never to just lower or increase pH. You should never try to lower your pH, and should pH be increased, it's really incidental to boosting kH.

If you need help with your water, start a thread, but there is almost always never a time that you'd want to lower pH.

[ElaineSelene 39]

What about lowering PH with vinegar or similar? Can anyone tell me about that?

The goal is never to just lower or increase pH. You should never try to lower your pH, and should pH be increased, it's really incidental to boosting kH.

If you need help with your water, start a thread, but there is almost always never a time that you'd want to lower pH.

Oh. Sorry...

[dnalex 13,633]

Haha don't be sorry. I just wanted to make sure that the point came across.

[ElaineSelene 39]

Haha don't be sorry. I just wanted to make sure that the point came across.

Its 5ml of vinegar too late... but other than that I won't do anything else... *blushes*