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RE: CO2 in Low (red) Light tanks

> Date: Sat, 16 Feb 2002 14:32:46 -0800 (PST)
> From: Scott Hieber

> Isn;'t this what everyone is after, more kinds
> of smaller plants?

For quite a number of reasons, yes. In my own case, it's a response to the
limited sizes of the tanks I keep (if I'm to keep as many as I need). If I
could "scale down" some plants just a little, I could possibly fit a
three-foot layout into a two-foot tank while increasing the perception of
depth. It would also widen the possibilities for _really_ small tanks - like
a ten-gallon that's no longer limited to just two or three workable

> I take it you mean a relatively low level of
> total light, but most of the light being red?
> As opposed to light that is relatively low in
> the red part of the spectrum?

The first case - lower light levels with the color primarily in the red

> Are you talking about more red spectrum than
> a common "pinky" type plant/aquarium bulb?
> As red as, say, the AH Supply 13 Watt "red"
> bulbs?

All of my work has been with two types of lamps - T12 fluorescents and High
Intensity Discharge. Other than Cool Whites, there's not a lot available in
my area in the way of even T8s, much less T5s and PC fluorescents. And my
discretionary income across the last decade or so has been close to
non-existent, precluding a lot of experimentation with newer technologies.

These two types of lamps are also part and parcel to the work I was doing at
the time in hydroponics. We used a mix of MV and HPS as main grow lights
because we felt they gave a better mix of blue and red, at the proper
wavelength, than a straight run of MH. It also allowed us to gradually fade
the light to red by dropping out some of the MV lamps to simulate the
decreasing angle of sunlight in Autumn and the resultant reddening it causes
(more atmosphere to penetrate = more blue to be scattered and attenuated).
Coupled with shifts in the diurnal phase, it gave us excellent control over
the life cycle of the annuals we were working with at the time. This in turn
translates to _multiple_ "growing seasons" within a single year - which the
folks working on hybrid strains appreciated immensely.

The fluorescents were quite handy for their diffuse lighting. They worked
best for seedlings and cuttings and allowed for even better blends of
lighting due to their wider color availability.

The "pinky" type of P/A lamp I'm most fond of is the Sylvania standard
GroLux - it puts out slightly more light than the GE P&A and holds up well
across time. I use a 3:1 mix of GroLux and GroLux WS (for my eyes), on a
16-inch water column, and a 12-hour diurnal (best mix for
tropical/temperate) as the "baseline" reference for growth, color and shape

Lighting measurements...hmmm...believe it or not, all of my lighting
comparisons are made with a little gardeners tool I've had since about 1988
or so. Picked it up at, of all places, Radio Shack. It's a combination
water/light meter that uses a bimetal probe for testing soil moisture and
what appears under the fresnel to be a small solar panel-type of gizmo for
light as part of the readout display (needle scale analog). As it has never
given me a problem (if it ain't broke, don't fix it) and I'm afraid to
"jinx" it's rather long life span through curious disassembly, it's for all
intents and purposes a hand-held "black box" for now.

I can't tell you the name of the darned thing, as Micronta is all that's
labeled anywhere - except for a little paper tag on the back (even it's
still there) that tells me the Micronta catalog number is 63-685. But having
played around with it in full daylight, along with a few neutral density and
polarizing filters, I can tell you that the 1-10 scale on the needle roughly
corresponds to straight up percentage points in intensity - 1 to 10 percent
of sunlight, in other words.

Using this little "do-hickey", I get a range of 2-8 from substrate to
surface. The tool's scale seems to follow the inverse drop-off of intensity
appropriately enough, and shows that most of the plants are receiving 5% of
sunlit intensity or less. Of course, this has no real validity as a
measurement - for one thing, I've never bothered to find out the spectra to
which it's most sensitive. That in turn means that I can't predict which
type of lamp affects it most. But using the _same instrument_ in all cases
at least helps me to maintain a consistency to _relative_ shifts in
different setups.

Since then, I guess I've just stuck with what I'm comfortable with and can
easily obtain in lighting, too. Ballasts and fixtures are easy to come by
when you catch some folks remodeling, and HID lamps are _very_ affordable if
you keep to things like security lighting at Home Depot/Lowe's rather than
specialized interest suppliers.

At any rate, I'm in no real position to comment on AH's available line.
Someone like Ivo would have a much better handle on a comparison question.

Speaking of spare money, right now I'm a little excited that the ACA
convention is scheduled for Atlanta this year - an hour's drive from the
house. This is, to me, every bit as fortuitous as the AGA's first being held
right here in Chattanooga! It will not only give me the chance to seriously
expand my stock, but allow me to meet a few more of the people I've only
"met" through e-mails and Lists across the years.

Now after _that_, I'll be saving in order to toss some business toward Dave
G - after almost six years of constantly mixing yeast bottles, I'm finally
ready to move up to regulated systems. Whew!

> BTW, thanks for the detailed response regarding CO2
> and low light.

Heh heh...I don't usually suffer from lack of detail, so I surely don't see
a problem here...