Basic chemistry question

[Nemo]

What water chemistry parameters would you ideally want in a planted tank?
pH, kH and gH?

My kH is very low, about 3 dKh causing pH swings. I want to minimise raising
the pH. What is the minimum kH needed to maintain a reasonably stable pH?

Thanks

[[email protected]]

"Nemo" > wrote in message >...
> What water chemistry parameters would you ideally want in a planted tank?
> pH, kH and gH?
>
> My kH is very low, about 3 dKh causing pH swings. I want to minimise raising
> the pH. What is the minimum kH needed to maintain a reasonably stable pH?
>
> Thanks

The issue is not so much an ideal pH, it's more an issue of the proper
CO2 level.
See pH/KH/CO2 chart/table=> www.sfbaaps.com

KH is fine 2-3 degree range.
If your pH is moving, it's moving for a reason, CO2.
The plants remove it, the pH goes up. At night, the CO2 from the air
slowly re enters the water and equilibrates the pH back down.
GH/KH are good in the 3 and up range. I am unaware of any upper limits
as few folks have KH's above 20 or GH's above 25 and I've kept plants
just fine in that water, so it's unlikley you'll encounter water
harder than that.

If you do not add enough CO2, the plants will sometimes, depending on
the species, go after the KH for the carbon, all algae can do this as
well.
If you only have say 1 degree of KH, if the CO2 is too low etc, then
you can use up all the KH.
Doing routine regular water changes prevents this depeletion along
with having enough KH in case this happens.
Also adding enough CO2 will also prevent this.

Do you have a non CO2 plant tank?

If you use CO2:, GH/KH 3 degrees or higher.
pH=> depends on the KH when adding CO2. See table, the two are
related, not independent measurements when trying to provide good
conditions for plants to grow.

It's all about CO2, that is what plants prefer(pH/KH combo).
GH=> just enough Ca++/Mg++ which are nutrients so the plant does not
run out.

Regards,
Tom Barr

[RedForeman ©®]

baking soda is/can be added as a buffer, it raises your kH and buffers your
pH enough to keep a stable pH for quite a while... I add 1 tbsp to every
10g, do your own math, and it gives a bump on pH and the buffer capacity is
in the volume you add... the more you add, the more your kH raises, but not
pH

for a planted tank, well, that varies IMHO.... I shoot for a pH of 6.6-7.6
on 3 different tanks the lower one has CO2, others don't

pH 6.6 and kH of 2-4 give you a range of 15-30ppm of CO2
pH 7.6 and kH of 2-4 give you a range of 1-3ppm CO2

Use this to find your CO2 levels and what is optimal for your tank and
water...
http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm

unless my 3 years of learning have lead me down the demented path, which
could happen...

--
RedForeman ©®


"Nemo" > wrote in message
...
> What water chemistry parameters would you ideally want in a planted tank?
> pH, kH and gH?
>
> My kH is very low, about 3 dKh causing pH swings. I want to minimise
raising
> the pH. What is the minimum kH needed to maintain a reasonably stable pH?
>
> Thanks
>
>

[Happy'Cam'per]

"RedForeman ©®" > wrote in message
...
> unless my 3 years of learning have lead me down the demented path, which
> could happen...

Been there done that :)
--
**So long, and thanks for all the fish!**

[Nemo]

Thanks for all the info RedForeman
Thanks to all who replied.


"RedForeman ©®" > wrote in message
...
> baking soda is/can be added as a buffer, it raises your kH and buffers
your
> pH enough to keep a stable pH for quite a while... I add 1 tbsp to every
> 10g, do your own math, and it gives a bump on pH and the buffer capacity
is
> in the volume you add... the more you add, the more your kH raises, but
not
> pH
>
> for a planted tank, well, that varies IMHO.... I shoot for a pH of 6.6-7.6
> on 3 different tanks the lower one has CO2, others don't
>
> pH 6.6 and kH of 2-4 give you a range of 15-30ppm of CO2
> pH 7.6 and kH of 2-4 give you a range of 1-3ppm CO2
>
> Use this to find your CO2 levels and what is optimal for your tank and
> water...
> http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm
>
> unless my 3 years of learning have lead me down the demented path, which
> could happen...
>
> --
> RedForeman ©®
>
>
> "Nemo" > wrote in message
> ...
> > What water chemistry parameters would you ideally want in a planted
tank?
> > pH, kH and gH?
> >
> > My kH is very low, about 3 dKh causing pH swings. I want to minimise
> raising
> > the pH. What is the minimum kH needed to maintain a reasonably stable
pH?
> >
> > Thanks
> >
> >
>
>

[Chuck Gadd]

On Tue, 20 Jan 2004 09:24:12 -0500, "Nemo" > wrote:

>My kH is very low, about 3 dKh causing pH swings. I want to minimise raising
>the pH. What is the minimum kH needed to maintain a reasonably stable pH?

A KH of 3 will not cause pH swings.

As long as there is SOME buffering (KH of 1 or more), then the KH is
NOT the cause of any pH swing. A low KH will result in a lower
overall pH value, but it won't change the pH swing.

If you are getting a pH swing, then some change in the acid level in
the tank is occuring.

In a non-CO2 injected planted tank, you will often see the pH rise
during the day, as plants strip out all CO2 from the water, making the
water less acidic. Then at night, CO2 levels return to the ambient
3-4ppm.

Since the KH isn't the cause of your pH swing, give more details about
your tank setup, and exactly what you are seeing with your pH
readings.


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

[Nemo]

Hi Chuck,
Thanks for your input.
My setup is fairly simple. I don't currently have a planted tank per se - it
is WIP.
Current setup:
- 25 gallons
- 5 plants
- 18 watts light (don't laugh please)
- no CO2
- 1 adult , 2 juvenile platies
- 5 neon tetras
- 2 pieces of mopani wood
- 300gph rated power filter
- 100W heater

gH = 3
kH = 3
Temp = 79-80 oF
pH = 7.8 - 7.2 (over a week say)

1-2 x 25% Water changes weekly
Tap water
gH = 3
kH = 2-4
pH = 8.0-8.2

Symptoms - dead neon tetras

[Michi Henning]

"Nemo" > wrote in message
...

> gH = 3
> kH = 3
> Temp = 79-80 oF
> pH = 7.8 - 7.2 (over a week say)
>
> 1-2 x 25% Water changes weekly
> Tap water
> gH = 3
> kH = 2-4
> pH = 8.0-8.2
>
> Symptoms - dead neon tetras

First thing to check would be ammonia, nitrite, and nitrate.
Especially with your high pH, any ammonia will be present
in (highly toxic) molecular form, which could be the cause
of the deaths.

Cheers,

Michi.

--
Michi Henning Ph: +61 4 1118-2700
ZeroC, Inc. http://www.zeroc.com

[Dan Drake]

On Tue, 20 Jan 2004 20:52:22 UTC, "RedForeman ©®" >
wrote:

> baking soda is/can be added as a buffer, it raises your kH and buffers your
> pH enough to keep a stable pH for quite a while... I add 1 tbsp to every
> 10g, do your own math, and it gives a bump on pH and the buffer capacity is
> in the volume you add... the more you add, the more your kH raises, but not
> pH

If you don't have CO2 injection, raising the KH must always raise the pH.
(Well, there are a couple of exceptions, but they're not of any use in
keeping your neons alive.) This is because there is a fixed amount of
carbonic acid in your water, determined by the amount of CO2 in the air.
The pH depends on the ratio of bicarbonate to carbonic acid; so increasing
the bicarbonate with the same amount of carbonic acid gives you higher pH.

Your fish and plants complicate this by moving CO2 in and out of the
water. But the atmosphere is always pulling the CO2 level back toward the
3-4 parts per million that's in equilibrium.

>
> for a planted tank, well, that varies IMHO.... I shoot for a pH of 6.6-7.6
> on 3 different tanks the lower one has CO2, others don't
>
> pH 6.6 and kH of 2-4 give you a range of 15-30ppm of CO2
> pH 7.6 and kH of 2-4 give you a range of 1-3ppm CO2

One thing is left out of this: if you don't have CO2 injection, your CO2
level *will* be set by the amount of CO2 in the air; 15-30 ppm is not
going to happen, because it's out of balance with the atmosphere. You can
mess with it, for instance by adding acid to the tank to bring down the pH
and increase the CO2; then some CO2 will escape from the tank into the
air, and the pH will go back up to nearly what it was before. "Nearly",
because the KH went down a little when that CO2 escaped into the air.

>
> Use this to find your CO2 levels and what is optimal for your tank and
> water...
> http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm

But remember -- not to belabor the point or anything -- that if you don't
add CO2 to the tank, your CO2 level will be 3-4 ppm. This means KH of 1 -
1.3 at pH of 7.0. A pity, because neons are happier at 7.0 than at 7.8.
There are buffering chemicals that will supposedly keep the pH reasonably
steady at 7.0 or so; if you use these buffers, just forget about KH and
CO2, because you're overriding them.


--
Dan Drake

http://www.dandrake.com

[smth.kvin]

First to check the ammonia, nitrite, nitrate. Especially your high pH, ammonia will attend any In the (highly toxic) molecules in the form, which may be the reason death.