non-phosphate buffers?

Recently learned that my water is soft and is contrbuting to an
unstable pH. Just wondering if anyone knows of any good buffers on the
market that dont contain phosphates. Most dont list the constituents.
Thanks for any info.

John


PS I dont really want to mess with baking soda due to poor buffering
capacity at pH values below 7.

Pittie thus spake:

Recently learned that my water is soft and is contrbuting to an
unstable pH. Just wondering if anyone knows of any good buffers on the
market that dont contain phosphates. Most dont list the constituents.
Thanks for any info.

Calcium Carbonate, available by mail or in *some* pharmacies.
Low dkH values only effect pH buffering at very low levels, 1dkH
gH doesn't really effect pH buffering, kH does.

PS I dont really want to mess with baking soda due to poor buffering
capacity at pH values below 7.

Never heard of such a thing. It is used by quite a few people.
Perhaps you are confusing pH buffers/modifiers with hardness?
JMHO.

Good Luck,

Greg G.

"Pittie" wrote in message ...
Recently learned that my water is soft and is contrbuting to an
unstable pH. Just wondering if anyone knows of any good buffers on the
market that dont contain phosphates. Most dont list the constituents.
Thanks for any info.

John


PS I dont really want to mess with baking soda due to poor buffering
capacity at pH values below 7.

First off, you don't NEED RO water for planted tanks, you may need it
for the fish and if you are a breeder etc, but RO or soft water is not
needed for the plants.

That is simply a plain _myth_.

If you have very soft RO type water, you do not need any pH down acid
"buffers".
All you need is baking soda for the alkalinity(KH)
Got the GH, Ca and Mg is all you needs, MgSO4, CaCl2 work well to
adjust this up.

You can use CaCO3 for both some GH and the KH but it's slow to
dissolve.

Ideally, a 50ppm range or about ~ 3 degrees for both KH and GH is
ideal for plants or HIGHER.

Most folks blend their tap with RO to get the desired KH/GH.

But this is not for the plants, they don't care about hard water.
They do care about CO2.


Regards,
Tom Barr

On Mon, 22 Dec 2003 10:23:48 -0500, "Pittie"
wrote:

PS I dont really want to mess with baking soda due to poor buffering
capacity at pH values below 7.

carbonate is the main buffer in the water. Baking Soda is sodium
bicarbonate. It will buffer the exact same, regardless of your pH.

But, as you raise the buffering, you raise the pH. Maybe this is the
point you are misunderstanding?


Chuck Gadd
http://www.csd.net/~cgadd/aqua

First I want to thank everyone for their replies. To clarify....

I have poorly buffered water from the tap (not RO, maybe my kH is low?) and
an unstable pH which tends to drop (presumably from mulm buildup in the
gravel). My substrate is kind of deep (4-5 inch) but I do keep regular 3-4
week 33% water changes. I need to breakdown the tank and clean out the
gravel (been set up~4yrs) but also want to start buffering the water to
maintain a stable pH. My issue with baking soda is that the pka is
somewhere in the mid 7's if I remember correctly. This would mean it is not
much of a help as a buffer below pH 7 where my fish like it. I may have
this a little confused but the principle is there I think. If I add sodium
bicarb my pH obviously shoots up above 7 but doesnt tend to stay there too
long. Just curious if there are any commercial preparations that will keep
the pH around 7 or slightly under with no phosphates in them. The bullseye
I added doesnt state either way but I am starting to see some hair algea so
I have my suspicions.

again thanks for everyones help,
John


"Pittie" wrote in message
...
Recently learned that my water is soft and is contrbuting to an
unstable pH. Just wondering if anyone knows of any good buffers on the
market that dont contain phosphates. Most dont list the constituents.
Thanks for any info.

John


PS I dont really want to mess with baking soda due to poor buffering
capacity at pH values below 7.

Shannon said:

First I want to thank everyone for their replies. To clarify....

I have poorly buffered water from the tap (not RO, maybe my kH is low?) and
an unstable pH which tends to drop (presumably from mulm buildup in the
gravel). My substrate is kind of deep (4-5 inch) but I do keep regular 3-4
week 33% water changes. I need to breakdown the tank and clean out the
gravel (been set up~4yrs) but also want to start buffering the water to
maintain a stable pH. My issue with baking soda is that the pka is
somewhere in the mid 7's if I remember correctly. This would mean it is not
much of a help as a buffer below pH 7 where my fish like it. I may have
this a little confused but the principle is there I think. If I add sodium
bicarb my pH obviously shoots up above 7 but doesnt tend to stay there too
long. Just curious if there are any commercial preparations that will keep
the pH around 7 or slightly under with no phosphates in them. The bullseye
I added doesnt state either way but I am starting to see some hair algea so
I have my suspicions.

It doesn't matter WHAT kH builder you use, they will all raise the pH.
Just the nature of the beast. Bullseye, pH up & down and similar
products are bad news - avoid them.

You have yet to state your kH, BTW.

There are no magic formulas that will force your pH to 7.0 and keep it
there - Period. Water chemistry is a complex series of reactions that
are constantly in ebb and flow.

With that in mind, perhaps it would serve you well to do a little
research on basic water chemistry and get it straight in your head
some of the more basic reactions. Not meaning to be a smart-ass.
You demonstrate a misunderstanding of general water chemistry.

Changing the kH WILL alter the pH - they are linked.
If you want more acid water, you lower the kH. The water will
naturally respond with a lower pH. Don't go below 2-3 kH because the
water loses it's buffering capacity. Buffering capacity is the
water's resistance to rapid chages in pH.

So, set the kH to 2-3 for adequate buffering, and use peat filtering
or CO2 injection to lower the pH if necessary. CO2 is used in Planted
tanks - if yours is not, go with the peat.

With that said, most fish are not really THAT particular about the pH
as long as it is STABLE. This is one good reason to avoid rip-off
chemicals like Bullseye - they cause constant fluctuations of the pH
level, not to mention the contents of your wallet. Work with the
water you have and things will go much smoother.

Look here for more good info:

www.thekrib.com

Good Luck,


Greg G.

If you want a pH of less than 7 and some KH, 50ppm or about 3 degrees,
it's easy.

Use CO2.

Add enough baking soda to raise the KH to 3 degrees.
Add enough CO2 gas **ONLY** to lower the pH to 6.5 and keep it there
within about .2pH units.
This is what you want to do for both fish and plants.

That's all you need to do.
If you want to understand WHY, well then you can spend a few hours
boning up on the topic, but you do not need to do this to keep
plants/CO2 fish etc.

Just do what I said.
The HOW is easy enough.

Regards,
Tom Barr

I have the same question as Shannon, and was wondering what is enough CO2
gas to lower the PH?

When u said enough, how much is it?

thanks.


" wrote in message
om...
If you want a pH of less than 7 and some KH, 50ppm or about 3 degrees,
it's easy.

Use CO2.

Add enough baking soda to raise the KH to 3 degrees.
Add enough CO2 gas **ONLY** to lower the pH to 6.5 and keep it there
within about .2pH units.
This is what you want to do for both fish and plants.

That's all you need to do.
If you want to understand WHY, well then you can spend a few hours
boning up on the topic, but you do not need to do this to keep
plants/CO2 fish etc.

Just do what I said.
The HOW is easy enough.

Regards,
Tom Barr

Thanks for the help. With a little luck I ca stabilize the situation with a
little more research.

Greg G. wrote in message
...
Carlos said:

I have the same question as Shannon, and was wondering what is enough CO2
gas to lower the PH?

When u said enough, how much is it?

Unfortunately, there is no fixed amount on this. There are simply too
many variables. Surface agitation, type of filtration, size of tank,
number and size of fish, etc.

Basically, you add CO2 in increasing amounts until the pH is where you
want it to be. It takes a while (days) to reach a stable point, so
you have to be patient when setting your rate of flow. Too much will
kill fish.


Greg G.

On Tue, 23 Dec 2003 05:57:53 UTC, "Shannon" wrote:

First I want to thank everyone for their replies. To clarify....

I have poorly buffered water from the tap (not RO, maybe my kH is low?) and
an unstable pH which tends to drop (presumably from mulm buildup in the
gravel)... My issue with baking soda is that the pka is
somewhere in the mid 7's if I remember correctly. This would mean it is not
much of a help as a buffer below pH 7 where my fish like it. I may have
this a little confused but the principle is there I think.

Well, so you start out knowing more than some of the people who have
replied.

However, the "effective" pKa of the bicarbonate system is a little above
6. There's a lot of room for confusion here, because the value given in a
table may or may not include a factor of 55 (a difference of log 55 in the
pKa) which represents the concentration of _water_ in the system. Also,
the calculation can be done in terms of CO2 pressure or H2CO3
concentration, related by a factor of about 30.

Here's a page that goes into detail on why carbonate works to keep blood
pH at 7.4 even though it shouldn't be very good at that _high_ a pH:
http://www.qldanaesthesia.com/AcidBaseBook/ab2_2.htm
Another take:
http://www.usbweb.com/reference2.asp?id_ref=23

Anyway, according to this and other sources, carbonate buffering should be
at its best for pH in the 6's, and I don't suppose you want to go much
below that.

Now for the bad news. In a chemical sense, bicarbonate works just fine at
pH 6, if you have enough of it. But you can't have enough of it. Your
water finds an equilibrium with the tiny amount of CO2 in the air; and the
more bicarbonate, the higher the pH. To have a low pH, you have to have
only a really low level of bicarbonate in the water -- and the low
concentration, sure enough, gives you bad stability.

You can break out of this by artificially forcing the amount of CO2 in the
water to stay waay above the level in the air. That's right, CO2
injection. (You knew that, and you don't want to do it, and that's why
you're asking, right?)

If I add sodium
bicarb my pH obviously shoots up above 7 but doesnt tend to stay there too
long. Just curious if there are any commercial preparations that will keep
the pH around 7 or slightly under with no phosphates in them. The bullseye
I added doesnt state either way but I am starting to see some hair algea so
I have my suspicions.

There are some non-phosphate buffers on the market, but I don't have them
handy. Poke around on the shelves of a good, big aquarium store, if
available, and you'll see some. I'm pretty sure SeaChem makes a pH-Down
replacement without phosphate. And they do say what's in the stuff;
generally it's a zwitterionic compound, maybe tin-something. How much
they'll help, I don't know.

--
Dan Drake

http://www.dandrake.com