PH, KH, CO2 interactivity

[Jason]

I am going to start injecting CO2 and wanted to make sure that I don't mess
anything up too bad. I plan on doing this with a 1 gallon DIY CO2 reactor.

I have a 50 gal (48x15x16) tank with the following parameters
120w of NO fluorescent
PH 7.5
KH 2
I think this gives me a CO2 level of about 2.5-3 ppm.

My question is should I raise the KH before injecting CO2. I plan on raising
the KH with baking soda. I think I understand the relationship between these
properties but would like to make sure. From my understanding if I raise the
KH to 4 it will bring the PH up to around ~8. And then injecting CO2 will
bring it back down.

Not sure if it is important but tank inhabitants are

4 neon tetras
3 glolite tetras
6 black mollies
6 white cloud danios
2 bronze cories
2 candy tetras
1 male betta
1 common pleco

7 apongeton plants growing from bulbs, not very big yet
dwarf grass
1 red melon sword
5 stem plants

I plan on adding some java fern, java moss and maybe some Amazon swords.

I can post pictures of what I have in the binaries if it will help.

[Colin]

Sounds absolutely fine to me - almost exactly the parameters I had (though
you have more light), and I add roughly half a teaspoon of baking soda with
the water change (40% odd weekly) to bring the KH up to 4.5-5, and then CO2
to bring the pH back down to 6.7 or so.

Might be worth two smaller CO2 reactors changed on alternate weeks to
stabilize the CO2 output - I got too much variation on my 46G with one
bottle. In the end I gave up and bought pressurized instead - far easier,
I've not touched it in months...

Colin


"Jason" > wrote in message
.com...
> I am going to start injecting CO2 and wanted to make sure that I don't
mess
> anything up too bad. I plan on doing this with a 1 gallon DIY CO2 reactor.
>
> I have a 50 gal (48x15x16) tank with the following parameters
> 120w of NO fluorescent
> PH 7.5
> KH 2
> I think this gives me a CO2 level of about 2.5-3 ppm.
>
> My question is should I raise the KH before injecting CO2. I plan on
raising
> the KH with baking soda. I think I understand the relationship between
these
> properties but would like to make sure. From my understanding if I raise
the
> KH to 4 it will bring the PH up to around ~8. And then injecting CO2 will
> bring it back down.
>
> Not sure if it is important but tank inhabitants are
>
> 4 neon tetras
> 3 glolite tetras
> 6 black mollies
> 6 white cloud danios
> 2 bronze cories
> 2 candy tetras
> 1 male betta
> 1 common pleco
>
> 7 apongeton plants growing from bulbs, not very big yet
> dwarf grass
> 1 red melon sword
> 5 stem plants
>
> I plan on adding some java fern, java moss and maybe some Amazon swords.
>
> I can post pictures of what I have in the binaries if it will help.
>
>

[Dave Millman]

Jason wrote:

> I am going to start injecting CO2 and wanted to make sure that I don't mess
> anything up too bad. I plan on doing this with a 1 gallon DIY CO2 reactor.
>
> I have a 50 gal (48x15x16) tank with the following parameters
> 120w of NO fluorescent
> PH 7.5
> KH 2
> I think this gives me a CO2 level of about 2.5-3 ppm.

According to Chuck's calculator
(http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm), this gives a CO2 level
of about 2ppm, which means you probably measured pH late in the day, after the
plants were sucking CO2 out of the water for a while. If you measure again first
thing in the morning, before photosynthesis starts, you will probably get pH
7.3. This yields a CO2 concentration of about 3ppm, which is the level in an
uninjected tank in equilibrium with the atmosphere.

> My question is should I raise the KH before injecting CO2. I plan on raising
> the KH with baking soda. I think I understand the relationship between these
> properties but would like to make sure. From my understanding if I raise the
> KH to 4 it will bring the PH up to around ~8. And then injecting CO2 will
> bring it back down.

At KH4 and a CO2 level of 3ppm (before lights on), pH will probably be about
7.6. After the plants start sucking the CO2 out of the water, it will probably
rise up to 7.8.

Now, regarding your CO2 plans: DIY CO2 works great. But to have a significant
impact on a 50 gallon tank will take a lot of CO2: at least two, 2-liter bottles
working in tandem (Start bottle A on Day 0, start bottle B on Day 5, change
bottle A on day 10, change bottle B on day 15, etc.) This works fine, many
people do it. If this sounds like too much work, consider pressurized CO2
instead.

[Jason]

"Dave Millman" > wrote in message
...
> Jason wrote:
>
> > I am going to start injecting CO2 and wanted to make sure that I don't
mess
> > anything up too bad. I plan on doing this with a 1 gallon DIY CO2
reactor.
> >
> > I have a 50 gal (48x15x16) tank with the following parameters
> > 120w of NO fluorescent
> > PH 7.5
> > KH 2
> > I think this gives me a CO2 level of about 2.5-3 ppm.
>
> According to Chuck's calculator
> (http://www.csd.net/~cgadd/aqua/art_plant_co2chart.htm), this gives a CO2
level
> of about 2ppm, which means you probably measured pH late in the day, after
the
> plants were sucking CO2 out of the water for a while. If you measure again
first
> thing in the morning, before photosynthesis starts, you will probably get
pH
> 7.3. This yields a CO2 concentration of about 3ppm, which is the level in
an
> uninjected tank in equilibrium with the atmosphere.
>
> > My question is should I raise the KH before injecting CO2. I plan on
raising
> > the KH with baking soda. I think I understand the relationship between
these
> > properties but would like to make sure. From my understanding if I raise
the
> > KH to 4 it will bring the PH up to around ~8. And then injecting CO2
will
> > bring it back down.
>
> At KH4 and a CO2 level of 3ppm (before lights on), pH will probably be
about
> 7.6. After the plants start sucking the CO2 out of the water, it will
probably
> rise up to 7.8.
>
> Now, regarding your CO2 plans: DIY CO2 works great. But to have a
significant
> impact on a 50 gallon tank will take a lot of CO2: at least two, 2-liter
bottles
> working in tandem (Start bottle A on Day 0, start bottle B on Day 5,
change
> bottle A on day 10, change bottle B on day 15, etc.) This works fine, many
> people do it. If this sounds like too much work, consider pressurized CO2
> instead.
>
>
>

I don't mind the work at all. I want to see what CO2 can do for me before I
spend alot of money on a pressurized system.

Jason