# Sodium Carbonate (Washing Soda) for Ph Buffer



## ncutler (Mar 5, 2009)

Hey guys,

I've started up a 15G tank for neolamprologus multifasciatus (multies - lake tang. cichlid). Since they are ok with plants, I've been CO2 injecting with plants. The fish haven't arrived yet, but I'm trying to get my Ph higher, so far my Ph maintains itself at 7.4 (goal is 8.2). My GH is 19 degrees, my KH 21 degrees.

I've now been trying sodium carbonate (not bicarbonate) since it buffers at a much higher Ph. But so far, the water hasn't budged from 7.4 (I've been very carefully adding more each time until I see a change). I was wondering if anyone knew if carbonic acid is relative to Ph, having greater influence as Ph gets higher?

Any tips on whether I could get my Ph to 8.2 or not with CO2. Thanks!


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## Zapins (Jul 28, 2004)

No, acid has the same effect everywhere on the pH scale. The scale is simply a way of telling the hydrogen ion content of a solution. Each pH number is 10x more acidic or basic then the one next to it, which means that there is 10x more acid or 10x less acid then the number next to it.

Alkalinity, or buffering capacity also does not depend on the pH. Once the buffer is overloaded by acid/base then the pH will move.

Carbonic acid will drop water to 5.5 in a tank with no other acids present assuming it is able to overcome the buffering capacity of the water. 

Why are you trying to get the pH up so high by the way? Add some calcium containing rock from the pet shop it will buffer the water at 8.2, or you can add crushed coral meant for salt water tanks (there is no salt in it).


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## ashappard (Jun 3, 2006)

@ncutler: I recommend investigating TDS ranges of another tank with the fish you plan on keeping, and reproduce those results in your own setup. Don't fret the change in pH due to added CO2. Watch that you do not add too much CO2, of course - but the change in pH by added CO2 is overrated when it comes to danger / fish health / breeding capacity.

on a possibly related note - ditch the pH controller if you are using one. Some think that is the best way to maintain stable levels of CO2 but it is not necessarily the case. A good steady flow control that holds a solid bubble rate is all that is needed. Good circulation within the aquarium also helps immensely.


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## ncutler (Mar 5, 2009)

Thanks guys. It's been driving me mad why it's stuck at 7.4. I've got argonite substrate + Seachem Onyx sand. I've also got crushed oyster shells in the filter but as I understand, the more alkaline the water, the less the water will absorb.

I'm also only using DIY CO2 on this tank, but my drop checker registers around 20-25 PPM.

The reason I'm trying to get the PH up above 8 is because of the lake tangs cichlids.


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## ashappard (Jun 3, 2006)

but is it really pH 8 they require, or a range of mineral content?
by checking TDS you can skip the effect of what CO2 does to pH and look more closely at mineral content. Of course it isnt perfect, TDS wont tell you the levels of individual minerals. But it's easy and less frustrating than chasing pH just to make a number.


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## wet (Nov 24, 2008)

On the same thought as above, which I think is logical, check out Travis Simonson's old heavily planted, densely planted Mbuna tank. His method, if I remember correctly, was simply lots of Calcium Carbonate and keeping algae down on the plants (since Mbuna are herbivores). I doubt high Ca is enough but you should be able to balance it with carbonates for both fish and plants. Travis used to post on the regular at AquariumAdvice.com as "travis_simonson" and here on APC as "travis". You'll find other stuff all over the net. If you're reading this, we miss you, Travis.


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## Zapins (Jul 28, 2004)

Yeah, I think they care more about TDS then ph. I've got some multifasciatus in 7.6 pH and a few 1000 ppm TDS and they are loving it. Calcium carbonate and magnesium sulfate is all I use.


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## ncutler (Mar 5, 2009)

Thanks a bunch guys, I've been trying to find this info out all over the place, you're really helping.

I am using Kent's Cichlid chemistry (focuses on TDS) and figure I must have good TDS if that's what was used to get my GH up. I will be likely getting a Ph monitor and TDS soon to be certain.

Zapins: any advice with multies? Want them to be my first attempt at species only breeding tank. Never seen them in person, but a couple of people just *love* them for their digging behaviours. Got 20-30 shells in my 15G. Making sure they are large escargo type ones so the multies don't get caught in them.


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## Zapins (Jul 28, 2004)

I've had them for about a month maybe a month and a half. They are really interesting fish and very easy to take care of. Just keep up with your water changes and they will be very happy. I've got mine in PVC elbows since its easier to move them around when I need to. I have 13 adults and 13 babies. Cool fish for sure! They also don't need a lot of room, they are all in a 10g and they certainly don't look crowded at all.


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## ncutler (Mar 5, 2009)

Thanks Zapins. I've had a heck of a time trying to get them. Got 2 LFS getting me in 6-8 each. I'm glad to know that even if both got them at the same time, my 15G will do just fine for all of them.


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## Diana K (Dec 20, 2007)

My GH is 19 degrees, my KH 21 degrees


Quit chasing pH. GH looks great! Sure, get a TDS meter.


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