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Old 26-07-2004, 01:02 PM
blank
 
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Default Is it safe to increase KH further?

My tank is 75gal low light, medium stocked community freshwater with at
least 1/3 plant cover, no CO2. For the past couple of weeks I've been
adding Flourish, Trace and Nitrogen at the recommended rates, and do a 50%
water change weekly. The plants have improved in colour and growth very
noticeably.

Tank water: pH 7.8, GH 6, KH 5, Nitrate 5, Phosphate 0.75 (Tap water is
8.4, 3, 3, 0.25)

I've finally begun to try to raise the KH in an attempt at increasing the
CO2 level, so added 3 tsp baking soda, which produced little change, then
added the recommended additonal 3 tsp today, which brought the KH up to 8
and didn't affect the pH. So far so good.

Looking at the standard CO2/KH/pH table, it seems I need to increase the KH
to about 20 to even get close to the optimal CO2 level. Which means I'm
going to be adding a lot of baking soda each week. My plan is to add 6 tsp
daily, monitor KH & pH, until I get up toward a KH of 20, and then, once I
know how much to add, add the appropriate amount with my weekly water change
in order to maintain the high KH. Does this sound like the right approach,
or am I about to create another disaster?


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Old 26-07-2004, 01:02 PM
Iain Miller
 
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Default Is it safe to increase KH further?


"blank" wrote in message
...
My tank is 75gal low light, medium stocked community freshwater with at
least 1/3 plant cover, no CO2. For the past couple of weeks I've been
adding Flourish, Trace and Nitrogen at the recommended rates, and do a 50%
water change weekly. The plants have improved in colour and growth very
noticeably.

Tank water: pH 7.8, GH 6, KH 5, Nitrate 5, Phosphate 0.75 (Tap water is
8.4, 3, 3, 0.25)

I've finally begun to try to raise the KH in an attempt at increasing the
CO2 level, so added 3 tsp baking soda, which produced little change, then
added the recommended additonal 3 tsp today, which brought the KH up to 8
and didn't affect the pH. So far so good.

Looking at the standard CO2/KH/pH table, it seems I need to increase the

KH
to about 20 to even get close to the optimal CO2 level. Which means I'm
going to be adding a lot of baking soda each week. My plan is to add 6

tsp
daily, monitor KH & pH, until I get up toward a KH of 20, and then, once I
know how much to add, add the appropriate amount with my weekly water

change
in order to maintain the high KH. Does this sound like the right

approach,
or am I about to create another disaster?


Increasing the Kh will not increase your CO2 level....only adding CO2 does
that (!)

Increasing KH without altering CO2 will increase your Ph so I'm not quite
sure how you managed to add Baking soda & not affect Ph....it doesn't
compute - suggest you test it again. Quite often you will see tap water
having a lower than expected Ph level - this is because it sometimes
(usually) contains artificially high levels of CO2 when it comes out the
tap. Water that has just been filtered through peat does the same thing
(only to a much greater extent). In both cases the excess CO2 will escape
over a matter of hours & the thing will settle back to the standard 2-3ppm.

You seem to have understood that there is a relationship between KH, Ph &
CO2 but just perhaps not how it works. The two variables are Kh & CO2. The
Ph is the product. Altering one of the variables (CO2 or Kh) will alter the
product (Ph) but it won't affect the other variable. So adding Kh won't
change your CO2 level & playing with CO2 levels won't affect your - Kh but
altering either one will affect the Ph.

Short answer, in order to increase CO2 you need to add it one way or
another.

HTH

Iain

rgds

I.






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Old 26-07-2004, 02:02 PM
blank
 
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Default Is it safe to increase KH further?


"Iain Miller" wrote in message
...


Increasing the Kh will not increase your CO2 level....only adding CO2 does
that (!)

I have read that water with a high KH holds CO2 better than low KH, so
that's why I'm attempting this.

Increasing KH without altering CO2 will increase your Ph so I'm not quite
sure how you managed to add Baking soda & not affect Ph....it doesn't
compute - suggest you test it again.


I've read that the pH will rise, but not necessarily in direct proportion.
My understanding (such as it is) was that I would be able to raise the KH
somewhat, without an immediate, correlative effect on pH. So I figured I am
OK so far. But will check it again tomorrow.

Quite often you will see tap water
having a lower than expected Ph level - this is because it sometimes
(usually) contains artificially high levels of CO2 when it comes out the
tap. Water that has just been filtered through peat does the same thing
(only to a much greater extent). In both cases the excess CO2 will escape
over a matter of hours & the thing will settle back to the standard

2-3ppm.

You seem to have understood that there is a relationship between KH, Ph &
CO2 but just perhaps not how it works.


Yes, that's often my problem

The two variables are Kh & CO2. The
Ph is the product. Altering one of the variables (CO2 or Kh) will alter

the
product (Ph) but it won't affect the other variable. So adding Kh won't
change your CO2 level & playing with CO2 levels won't affect your - Kh but
altering either one will affect the Ph.

Short answer, in order to increase CO2 you need to add it one way or
another.

I'm hoping that the considerable expense of dosing Excel regularly at fairly
high rates will help with the CO2 level, and that increasing the KH will
make the CO2 more available to the plants. I'm not looking for spectacular
plant growth, just a decent looking display that will enhance the tank and
make life more enjoyable for the fish. Thanks for your contribution to my
education.









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Old 26-07-2004, 05:02 PM
 
Posts: n/a
Default Is it safe to increase KH further?

I'm hoping that the considerable expense of dosing Excel regularly at fairly
high rates will help with the CO2 level, and that increasing the KH will
make the CO2 more available to the plants. I'm not looking for spectacular
plant growth, just a decent looking display that will enhance the tank and
make life more enjoyable for the fish. Thanks for your contribution to my
education.


Excel sounds like the deal for you. As long as your light is lower,
you should be fine.

Adding KH, -HCO3 in this case can help plants grow if they are CO2
limited, a few plants can use thie HCO3, most all algae can as a rule.

Adding it will not increase or lower the CO2 level. That will be the
same no matter what the KH.

Try this, add baking soda to a glass of water and measure the pH/KH do
the same for a glass of water without adding the baking soda. The CO2
levels should be identical.

The KH will be different, the total carbon will be higher in the one
with bakign soda added, but the CO2 is still the same.

If you want to increase the CO2 level, add CO2 gas only.
That's what the plant need/want. We use pH/KH to measure CO2, not
control it's level.

CO2 gas is cheap, the gas tank systerms run about 125-150$, the DIY
are good for small tanks and are almost free.

Regards,
Tom Barr
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Old 26-07-2004, 09:02 PM
xtr396472
 
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Default Is it safe to increase KH further?

I read some where that using baking soda your pH Max's out around 7.6
Your tank specs are similar to mine (New Zealand). I use excell and ferts in
a AR850 tank Its alot tidier than my old system of bottles and diffuses
etc.
Mike





"blank" wrote in message
...
My tank is 75gal low light, medium stocked community freshwater with at
least 1/3 plant cover, no CO2. For the past couple of weeks I've been
adding Flourish, Trace and Nitrogen at the recommended rates, and do a 50%
water change weekly. The plants have improved in colour and growth very
noticeably.

Tank water: pH 7.8, GH 6, KH 5, Nitrate 5, Phosphate 0.75 (Tap water is
8.4, 3, 3, 0.25)

I've finally begun to try to raise the KH in an attempt at increasing the
CO2 level, so added 3 tsp baking soda, which produced little change, then
added the recommended additonal 3 tsp today, which brought the KH up to 8
and didn't affect the pH. So far so good.

Looking at the standard CO2/KH/pH table, it seems I need to increase the

KH
to about 20 to even get close to the optimal CO2 level. Which means I'm
going to be adding a lot of baking soda each week. My plan is to add 6

tsp
daily, monitor KH & pH, until I get up toward a KH of 20, and then, once I
know how much to add, add the appropriate amount with my weekly water

change
in order to maintain the high KH. Does this sound like the right

approach,
or am I about to create another disaster?






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Old 26-07-2004, 09:02 PM
Iain Miller
 
Posts: n/a
Default Is it safe to increase KH further?



I'm hoping that the considerable expense of dosing Excel regularly at

fairly
high rates will help with the CO2 level, and that increasing the KH will
make the CO2 more available to the plants. I'm not looking for

spectacular
plant growth, just a decent looking display that will enhance the tank and
make life more enjoyable for the fish. Thanks for your contribution to my
education.


As before, the only way to make CO2 more available to your plants is to add
CO2 to the water. You'll see people talking about maintaining CO2 levels of
between 20 & 30ppm when doing this and its quite common for aquarists to aim
for that.

That said ANY extra CO2 you add will be greatfully recieved. On on of my
tanks ( about 45 USG) I use one of those Hagen things that's supposed to be
for a 10-15G tank. It hardly raises the detectable CO2 level at all but
there is no doubt the plants appreciate it.


I've gone to the other extreme as well (25ppm) through a gas bottle system &
the plants go into what can only be described as "hypergrowth". I find it
too frenetic - stuff grows much too fast so even there I have tuned the
thing down to be only 10ppm or so.


rgds

Iain


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Old 27-07-2004, 06:36 AM
Robert Flory
 
Posts: n/a
Default Is it safe to increase KH further?


"blank" wrote in message
...

"Iain Miller" wrote in message
...


Increasing the Kh will not increase your CO2 level....only adding CO2

does
that (!)

I have read that water with a high KH holds CO2 better than low KH, so
that's why I'm attempting this.

Increasing KH without altering CO2 will increase your Ph so I'm not

quite
sure how you managed to add Baking soda & not affect Ph....it doesn't
compute - suggest you test it again.


I've read that the pH will rise, but not necessarily in direct proportion.
My understanding (such as it is) was that I would be able to raise the KH
somewhat, without an immediate, correlative effect on pH. So I figured I

am
OK so far. But will check it again tomorrow.

SNIP ....

If kH is the only thing buffering a tank, adding baking soda will give you a
rise in pH, however lots of other chemicals in the mix can minimize the
affect of adding some chemical increase kH. Gravel really full of organic
material is one of them. I'm sure a chemist could suggest others. Seachem
sells an acid buffer that you use with an alkaline buffer to set a tanks pH.
It will suppress the response of adding baking soda.

Any chemists around?

Bob


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