CO2 requirements for Low Light Plants

[Daza]

Because of the depth of my tank (30inchs) and the limited lighting
(3x25watt tubes) I've stocked the tank with plants that require
low/medium light. I've included the stock list below but am wondering
if the plants which are growing ok but slowly would benefit from the
addition of CO2, or because of the low light and there for slow
growing species I've got, do they not require much CO2. Thanks in
advance.....Darren.
Echinodorus Bleheri, Cryptocoryne Wendtii, Micosorium Pteropus,
Lobelia Cardinalis, Anubia barteri v.nana, Anubia barteri v.barteri,
Cryptocoryne pontederiifolia, Hygrophila corymbosa, Cryptocoryne
undulata(broad).

[Amit]

And what is the tank size ???
"Daza" > wrote in message
om...
> Because of the depth of my tank (30inchs) and the limited lighting
> (3x25watt tubes) I've stocked the tank with plants that require
> low/medium light. I've included the stock list below but am wondering
> if the plants which are growing ok but slowly would benefit from the
> addition of CO2, or because of the low light and there for slow
> growing species I've got, do they not require much CO2. Thanks in
> advance.....Darren.
> Echinodorus Bleheri, Cryptocoryne Wendtii, Micosorium Pteropus,
> Lobelia Cardinalis, Anubia barteri v.nana, Anubia barteri v.barteri,
> Cryptocoryne pontederiifolia, Hygrophila corymbosa, Cryptocoryne
> undulata(broad).

[Chuck Gadd]

On 8 Feb 2004 11:22:27 -0800, (Daza) wrote:

>low/medium light. I've included the stock list below but am wondering
>if the plants which are growing ok but slowly would benefit from the
>addition of CO2, or because of the low light and there for slow
>growing species I've got, do they not require much CO2. Thanks in

Tropica had some research on their website that showed that CO2
addition can actually improve growth more in low-light situations than
in medium or high light.

This doesn't mean CO2 can make up for insufficient lighting. The
light needs to be at least enough for the plants to grow.



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

[[email protected]]

(Daza) wrote in message >...
> Because of the depth of my tank (30inchs) and the limited lighting
> (3x25watt tubes) I've stocked the tank with plants that require
> low/medium light. I've included the stock list below but am wondering
> if the plants which are growing ok but slowly would benefit from the
> addition of CO2, or because of the low light and there for slow
> growing species I've got, do they not require much CO2. Thanks in
> advance.....Darren.
> Echinodorus Bleheri, Cryptocoryne Wendtii, Micosorium Pteropus,
> Lobelia Cardinalis, Anubia barteri v.nana, Anubia barteri v.barteri,
> Cryptocoryne pontederiifolia, Hygrophila corymbosa, Cryptocoryne
> undulata(broad).

Adding CO2 will maximuize the Light compensation point(lowest amount
that the plant will "grow" at) for any plant I'm aware of.

You will get the maximum use from low light by adding CO2, dosing KNO3
etc.

This has been shown in numerous studies on aquatic photosynthesis.
Once a week dosing(KNO3, KH2PO4, Traces etc), with good CO2 levels
20-30ppm will yeild excellent results at low light.

Regards,
Tom Barr

[[email protected]]

> Tropica had some research on their website that showed that CO2
> addition can actually improve growth more in low-light situations than
> in medium or high light.
>
> This doesn't mean CO2 can make up for insufficient lighting. The
> light needs to be at least enough for the plants to grow.
> Chuck Gadd
> http://www.csd.net/~cgadd/aqua

The research was already there awhile ago, several papers, one by
Jensen from 1989 in particular shows this clearly with the
assimilation irradience curves shown for various macropytes. Other
papers are also out there documenting this.
The Tropica site has it more distilled down for the hobbyist.
I take that another step further but if you go too simple, folks think
you are full of bull, too in depth and too much research mumbo, they
miss your point.
So a book is in order:)

Regards,
Tom Barr

[Shawn P. Good]

> This doesn't mean CO2 can make up for insufficient lighting. The
> light needs to be at least enough for the plants to grow.
>
> Chuck Gadd
> http://www.csd.net/~cgadd/aqua

So - what IS sufficient light for plants to grow ? I'm having a hard time
establishing plants in my tank. Even hornwort is dying - all the little
needles are littering the bottom of my tank. I've ordered a CO2 system -
it's on its way. But I know I need to change my light, I just don't know
how.

I have a 55gal tank - it's 48" long, 20" high and 12" deep. I have a
stanard one-bulb hood on it - the kind where there are 2 lids you can lift
at the front to feed the fish. Right now I have one 40-watt bulb. Is there
some formula for figuring out wattage ? Can I buy a 75-watt or a 100-watt
bulb for this one-bulb hood ? Do I need a new hood ?

Thanks for any and all advice.

shawn

[Aqua]

> I have a 55gal tank - it's 48" long, 20" high and 12" deep. I have a
> stanard one-bulb hood on it - the kind where there are 2 lids you can lift
> at the front to feed the fish. Right now I have one 40-watt bulb. Is there
> some formula for figuring out wattage ? Can I buy a 75-watt or a 100-watt
> bulb for this one-bulb hood ? Do I need a new hood ?

I dont know about your current hood but you need minimum two more
40watt bulbs. This will give you little more than 2 watts per gal. Or
go for 2x55w bulbs.

Regards
Dominic

[Chuck Gadd]

On 10 Feb 2004 19:43:47 -0800, (Aqua) wrote:

>I dont know about your current hood but you need minimum two more
>40watt bulbs. This will give you little more than 2 watts per gal. Or
>go for 2x55w bulbs.
>

I've seen a 55g tank using just 2 40w tubes. It's on the low end of
the lighting scale, but it's enough for many of the less demanding
plants.



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

[Harry Muscle]

"Aqua" > wrote in message
m...
> > I have a 55gal tank - it's 48" long, 20" high and 12" deep. I have a
> > stanard one-bulb hood on it - the kind where there are 2 lids you can
lift
> > at the front to feed the fish. Right now I have one 40-watt bulb. Is
there
> > some formula for figuring out wattage ? Can I buy a 75-watt or a
100-watt
> > bulb for this one-bulb hood ? Do I need a new hood ?
>
> I dont know about your current hood but you need minimum two more
> 40watt bulbs. This will give you little more than 2 watts per gal. Or
> go for 2x55w bulbs.
>
> Regards
> Dominic

You can probably get away with adding just one more bulb, that would give
him almost 1.5 wpg, which would be ok for medium light plants. Adding one
more bulb should be doable without having to get a new hood, adding two
would probably require a bigger hood. You can always switch to compact
fluorescent though.

Harry




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[Harry Muscle]

"Shawn P. Good" > wrote in message
...
>
> > This doesn't mean CO2 can make up for insufficient lighting. The
> > light needs to be at least enough for the plants to grow.
> >
> > Chuck Gadd
> > http://www.csd.net/~cgadd/aqua
>
> So - what IS sufficient light for plants to grow ? I'm having a hard time
> establishing plants in my tank. Even hornwort is dying - all the little
> needles are littering the bottom of my tank. I've ordered a CO2 system -
> it's on its way. But I know I need to change my light, I just don't know
> how.
>
> I have a 55gal tank - it's 48" long, 20" high and 12" deep. I have a
> stanard one-bulb hood on it - the kind where there are 2 lids you can lift
> at the front to feed the fish. Right now I have one 40-watt bulb. Is
there
> some formula for figuring out wattage ? Can I buy a 75-watt or a 100-watt
> bulb for this one-bulb hood ? Do I need a new hood ?
>
> Thanks for any and all advice.
>
> shawn
>
>

Just one bulb is not enough. The formula is 1 foot per 10 watts, so your
four foot bulb is 40 watts (it might actually be 32 watts depending on the
ballast, but for watts per gallon measurements, we take it as a 40 watt
bulb). A general rule is to aim for around 2 wpg (watts per gallon),
however, if you stick to low/medium light plants you'd probably be fine with
about 1.5wpg. You can get 1.5wpg by adding one more 40w bulb. That would
require some DIY modifying of the hood. Unfortunately there's no such thing
as just buying a more powerful bulb for your hood without having to change a
whole bunch of other things. If you're not into DIY too much, try checking
out ahsupply.com. They sell kits that should fit your hood. They come with
compact fluorescent bulbs, which are quite different that what you've got
right now, but they produce way more light for the amount of room they take,
then again, they are alot more expensive to rep , which btw, you'll have
to do about once a year, not matter which bulbs you use.

Harry




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[Giancarlo Podio]

I don't think you will have a lot of luck with just one tube. However
hornwart, being a floating plant and therefore closest to the light,
is probably suffering from something else rather than insufficient
lighting.

2x40W T12 tubes or 2x32W T8 tubes work well for low light setups, I
think this would be the minimum you want to consider. If you have CO2
on it's way you may want to consider a little more light. The
all-glass tripple T8 fixture worked very well in my 55g tank, as did
2x55W compact flourescent retrofit from www.ahsupply.com

If you can reach around 2 watts per gallon you should be able to grow
just about anything.

Hope that helps
Giancarlo Podio

[Art Giacosa]

Don't go overboard ording equipment such as CO2 until you have your
lights in order. Although not a great rule, I would suggest you aim
for 2-3 watts per gallon to start. Plants need enough light to
photosynthesize. Each plant has a minimum amount of light they need
in order to photosynthesize enough to provide it with its minimum
requirements. As you have many different species in your aquarium,
you must focus on satisfying your most demanding plant as the others
will, by default, receive enough light.

Regards,

Art Giacosa
http://www.aquaticplantcentral.com

[Mike Edwardes]

"Shawn P. Good" > wrote in message >...
> So - what IS sufficient light for plants to grow ? I'm having a hard time
> establishing plants in my tank. Even hornwort is dying - all the little
> needles are littering the bottom of my tank.

Hornwort problem could well be temperature rather than light. Try
some at 70F - it'll race away!

Mike.
--
Mike Edwardes Tropicals
http://mike-edwardes.members.beeb.net