Raising KH thru baking soda

[Golfmad]

Hi

We generally use baking soda to raise our KH/PH. In one of Sera's web sites it says:

Now that you know you must test your pH values, it is necessary to adjust them. Again, old common knowledge was to add Baking Soda to the water to adjust it. This is not a good recommendation, as Baking Soda does not have a buffering agent to help stabilize the pH. If you were to add Baking Soda to the water, the pH would increase, and then fall again later.

Is this true ?

Rgds,Kelvin

[juggler]

Baking Soda by itself is alkaline. CO2 dissolving in water makes weak carbonic acid and would neutralise the alkali.

So Sera is recommending us to buy their kH-up products? Anyone used that before? Does it not raise the pH at the same time?

[Blue Whale]

I got KH Up but not sera brand for $7.20 and $1 for Bicarbonate of Soda (Baking Soda).

My KH has not gone much down after a week of use but for Baking Soda...they drop in some 1 to 2 days.

You be the judge.

[PeterGwee]

That's weird...I don't see my KH dropping over the week unless I do a water change. I'm currently using baking soda...

The other possibility of your KH dropping could be that your CO2 is low during that period and you have plants that can extract carbon from bicarbonate thus causing the drop..

[Blue Whale]

Ha Ha..dunno also. But its okay...currently KH stable. Quite happy with it.

[juggler]

----------------
On 5/13/2003 1:43:27 PM

I got KH Up but not sera brand for $7.20 and $1 for Bicarbonate of Soda (Baking Soda).

My KH has not gone much down after a week of use but for Baking Soda...they drop in some 1 to 2 days.

You be the judge.
----------------

For me, my kH comes from coral chips in my filter -- a little can last a long time.
Drawback is that it cannot be controlled except by water change. It keeps rising but I roughly know the schedule to keep it within 4~5 dkH.

[Golfmad]

----------------
On 5/13/2003 1:43:27 PM

I got KH Up but not sera brand for $7.20 and $1 for Bicarbonate of Soda (Baking Soda).

My KH has not gone much down after a week of use but for Baking Soda...they drop in some 1 to 2 days.

You be the judge.
----------------

Hi Knightstriker

I am more than aware of the costs associated with a PH Up product vs baking soda. However, I was more interested in their claims re buffering capabilities. I initially suspected that its to sell their products but wanted to hear what other forumers say.

Hi Juggler

Tks for info. I am very interested in your use of coral chips. What sort of chips are these and how fast does the KH rise if you do not change the water. How big is your tank and how much is used ?

Excuse my silly question here but if the KH rises constantly,would that not mess your CO2 levels ? I always get the impression that our KH should alway be held constant and control should be thru PH via co2 injection.

Rgds, Kelvin

[IUnknown]

This was from ADP, its from a killies forum so maby he didn't take Co2 into account,

Allen wrote:
> Hardly. Carbonate=Carbon=basic building block for organic life forms. (it
> also raises KH or Carbonate Hardness.)

Sorry Boat, must stick my nose in here.

As a chemist, I'm a decent electrical engineer, but have been living
with the crappy nomenclature in the aquaria world too long. See Geo.
Slusarczuk's various articles (APD archives, the Krib, etc.) on this
subject. Forget the term "Carbonate Hardness." It just means alkalinity.

>
> It is only as temporary as your next water change. Baking soda provides a
> buffer for the water and helps maintain a pH of about 8.0 to 8.2. It is not
> a "pH up" type chemical like an alkalinity booster, it is a buffer.

This is so mixed I don't quite know where to start. It *is* a "pH-up"
booster and it is a (part of a) buffer. Its primary effect is to simply
raise the alkalinity of pure water. Check the real definitions (not the
warped translations of some early aquatic articles from the German).

It is temporary if it goes away when the water is heated to boiling. As
part of the CaCO3/bicarbonate buffer system, it does exactly that,
precipitating out CaO (or CaOH?) as boiler scale and releasing CO2 to
the air. That's how they *defined* that abortion called "temporary
hardness."

It is also temporary in that Vals and some other plants can directly
extract their CO2 from it, and hence reduce it in the water column.

> Please
> guys do some homework that is all it takes.

BTDTBTWW!

>
> Boat
> (now wondering why he ever entered this conversation)

Me too. What am I doing here without even my rubber book (CRC Handbook)
to cover my nakedness?

>
> ps- things like peat and driftwood an such do suck dissolved solids out of
> the water, so Baking soda will have to be amended every now and then if
> there is a hardness sink such as these.

Those are primarily cation exchangers, AFAIK, so should have no effect
whatsoever on the bicarbonate concentration (alkalinity). Their released
tannins (tannic acid?) may, of course, somewhat neutralize the buffering
effect of sodium bicarbonate. [That's per the definition of alkalinity,
isn't it?]

>
> Allen "Boat" Boatman
> Lutz, FL
> TBAS, SKS, AKA 08298, SAA 96, CRLCA, NANFA
>
> Never, under any circumstances, take a sleeping pill and a laxative
> on the same night.

Now *that* sounds like really good advice!

Wright

--
Wright Huntley -- 209 521-0557 -- 731 Loletta Ave, Modesto CA 95351

"The right of self-government does not comprehend the government of others."
-- Thos. Jefferson --

That's what Independence Day is all about, isn't it?

[juggler]

Kelvin:

Using coral chips for kH can be a little hard to control but it is cheap.
For my 2.5ft tank, I used only a handful (about the amount you can hold in a slightly closed fist) tied in a netting and placed in the filter. Maybe you need a little more for bigger tanks. But you can control the kH somewhat by adding or removing the coral chips.

After a 50% water change per week, with my rate of CO2 injection, the kH raises to 4 or 5. So I can say about the rise is about 2 dkH per week. The kH will go higher and higher if there's no water change done. Not to worry, there's no harm to plants. But fish may not like the higher gH that comes from the coral chips.

Chuck's mentioned the below, which you might want to take note, in his article at http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm:

There is on case I've seen where the addition of CO2 resulted in an increase in KH. This can happen when you have something in the tank that dissolves carbonate into the water. Seashells, crushed coral, and many gravels and rocks will do this. With the addition of CO2, the water turns more acidic, which will increase the dissolving of the minerals. It appears that increasing CO2 raises the KH, which isn't really the case. The dissolving minerals raise the KH, and the increase in KH results in an increase in pH. In a system using a pH probe and controller to regulate CO2 levels, this can have fatal consequences, since the pH controller will keep trying to lower the pH, but as more CO2 is dissolved, it lowers the pH, which raises the KH, which raises the pH. So you now have more CO2, but the same pH. So the controller adds even MORE co2. And it will keep going. So it's important to know your KH whenever using pH to judge CO2 levels.

Lastly, I went for coral chips because they supply me the Ca and Mg needed for planted tanks. The pH rise from the dissolving corals can be neutralised somewhat by the CO2 injection.

[Golfmad]

Tks Juggler and others for your comments and help here. I have another silly question here. Now if I use baking soda to control my KH, PH can be controlled by CO2 injection.

Now can I use baking soda to control and PH up/down to control PH ? What does that do to my CO2 ? Is KH up/down the same as PH up/down ? My mind can't click on this one.

Rgds,Kelvin

[vinz]

Let's see.

Fix CO2
- raise KH -> raise pH
- lower KH -> lower pH
It's hard to lower KH. The easiest is to change water (assuming the new water has lower KH). The new water likely contains lower levels of CO2 too, so the pH is effected by more then one way. You'll have to wait till the CO2 saturates the water again.

Fix KH
- raise CO2 -> lower pH
- lower CO2 -> raise pH

Fix pH - can't be done easily, if at all.

[juggler]

----------------
On 5/14/2003 4:38:40 PM

Tks Juggler and others for your comments and help here. I have another silly question here. Now if I use baking soda to control my KH, PH can be controlled by CO2 injection.

Now can I use baking soda to control and PH up/down to control PH ? What does that do to my CO2 ? Is KH up/down the same as PH up/down ? My mind can't click on this one.

Rgds,Kelvin


----------------

Baking Soda is alkaline and raises kH, so pH and kH goes up.
pH UP/DOWN products should alter the pH only, though I have not tried it before.
kH UP/DOWN - never tried those before.

It gets more *chim* if you add gH to the discussion.

There's more info at http://www.thekrib.com/Plants/CO2/

[Golfmad]

Hi Juggler

If chim for you,then very terrible for me. Anyway, looks like there is no clear answer here. For my purposes, just knowing that baking soda will do the trick is sufficient. Anyway, I will try to see how the coral chips will affect my tank.

Tks,Kelvin

[juggler]

Sorry, shouldn't say *chim*, maybe "more exciting".

[IUnknown]

Juggler, also be careful with your ph. With baking soda it goes over 8.0 without Co2 injection.

[juggler]

Thanks. I am using coral chips for my kH supply. And it can also go to pH 7.6 if CO2 is low.