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Re: lighting & algae




> Re: Algae and Incandescent Lighting

> Incandescent lights are high in red and low in blue, at around 3000K.
> Dennerle also notes that many "plant lights" (such as Triton) were developed
> in tests using algae as a subject. Which is to say, those lights grow algae
> well, 

And they grow plants very well too. They should make that point as well.

but may not be good for planted aquaria for that very reason. The
> color rendering index (CRI) of most low light temperature lamps is not good
> compared to lamps in the 5000-6500K range lamps. So a mix of both is the
> solution that is frequently used.>>>

Folks can postulate as to what color temp  etc causes an algae. If there's
enough of it and within a range of 3000-8000K you will be fine(not all 7100
K blue bulbs though etc:) or other blatant extremes). It may look strange:)
but these will grow most every plant pretty well with little algae issue.
I've had all these weird a** lights and spent a fair bit of time with each
type. They all can grow plants very well. I liked the quartz 12v of all the
unorthodox lighting set ups. MV and HPS did very well but looked too weird
for my taste. The QTL's (quartz track lighting) were around 3000K and grew
every type of plant species(200 sp.) that folks keep. The color was very
nice actually and had a MH ripple effect on the water's surface. Very
cool.You can get hair algae and BBA with them as well. GW is absent from
every attempt to get it to grow. Suppose I should try again:)
Tritons do not cause algae, hobbyist do:) All these one bulb temp's do not
promote algae as many lighting/aquarium companies would have you believe. It
seems to only really count to have a nice color mix for our eyes and some
mix for the plants in enrich their color and health. A mix seems to help
plants over one color temp only though. But I can get the same results with
a single temp as well. Some plants fade color in red only temps. Best color
is in the 6700 range for myself.
I can do both and have multiple times. Question: So is it the light, or the
grower? Answer: It is the grower.

You can buy a 3000, 4000, 5000, 5500, 6500, 6700K, 8000K, gro-lux, triton,
vita, power glow etc and these will all grow your plants very well without
algae. Don't blame the lamp. A broad spectrum seems to be the best for color
and health of the plants themselves. Most tri phosphor FL's do well. A
certain spectrum does not promote algae anymore than it does promote plant
growth. They really are not that far apart concerning light generally. Both
use photosynthesis and chlorophyll. There are some differences in these
areas but not that much generally for what we are trying to accomplish.

2 X 20 watt Fl's on each side of a 55 gallon tank with fast growers will
make a good test as well.
You can have them separately on 20 gallon tanks as well.  I've done both and
each set up could produce the desire results, good plant growth and
little/no embarrassing algae. Some colors look nicer was all I found. Sure
if I let a tank go off a little you would get algae but that happens with
all tanks regardless of K light color:). The double 2x20 watt 55 gallon tank
had the same chemistry being on equal halves of the same tank. Algae was not
anymore present on one side compared to the other concerning lighting. If it
**was** the color temp alone that would have not been the case time and time
again. But then perhaps the chemistry from one side was helping the other.
This doesn't seem likely either since the tanks by themselves didn't show
much/no differences as well. It seem to me it must be something else, CO2 -
nutrients etc.
Think about it. Lights vary the least of all of our basic plant needs. They
put out light the same if on a timer every day. They have close to same
intensity most of their life, there is some decay and drop off etc. Get
decent ones and do not worry. PC's seem about the best overall to suit every
set up just about. I've used 6700's for several years, I'm very happy with
them. I still have not had one burn out yet(4 years) but a few on some reef
folks tanks have after 2 1/2 years. Still, not bad:)

> "Q:  I was told that there is a certain type of fluorescent light that is
> better for 
> plants than algae.  Is there any evidence for algae requiring a different
> light 
> spectrum than plants?
> 
> "A: No.  Many algae readily adapt to light spectral changes, probably more so
> than plants.  However, full-spectrum light, which usually has a fair amount of
> blue light, may stimulate algal growth more than light sources with less blue
> light 
> (e.g. 'cool-white' fluorescent, *incandescent* light, and high pressure sodium
> lamps).  THIS IS BECAUSE BLUE LIGHT MAKES IRON IN THE WATER
> MORE AVAILABLE TO THE ALGAE, THEREBY STIMULATING ITS
> GROWTH (see page 168)."

Ah... and the plants as well:) They can use it as well and do. If you have
lots of plants they will get it fast. We add iron that is available to the
algae to our water as well in many cases for our plants. Does adding iron
cause algae as well? Don't plants use it also? Depends on whether you like
or prefer water column dosing or not really. And even then the amounts of fe
released in a well planted tank would be utilized fast.
The answer in the beginning was "No" recall.

> "Different investigators demonstrated iron photoreduction using a variety of
> light
> sources ('cool-white', 'daylight' and 'vita-lite' fluorescent bulbs as well as
> sunlight).  However, UV and blue light induce the most photoreduction, because
> only wavelengths below about 500 nm are energetic enough to break the
> chemical bonds [31] (5)."
> 
> Endnote [31] is a reference to  Morel, FMM (1983) _Principles of Aquatic
> Chemistry_, p. 371
> 
> Footnote (5) says "The 280 to 400 nm portion of the light energy spectrum
> encompasses UV (ultraviolet) light, while the 400 to 500 nm range consists of
> violet and blue light..."
> 
> --- p. 168
> 
> ===================
> 
> On a personal note, I'm a little saddened to think 6700K CFs, whose spectrum
> I 
> prefer on esthetic grounds, may end up giving algae a better chance in life.

I disagree with you. I have them and don't have algae problems. Look at your
nutrients and CO2.
That's where your problem lies. Algae grazers sure help too.

The amount of UV iron breaking light energy is not that much comparing our
little weak FL's bulbs(then only that small portion of blue spike in there
as well) to that of sunlight which much of the references draws from. Quite
a big difference there. Perhaps a UV sterilizer may cause some breakdown. I
maintained a tank with a UV that ran 24/7 and it showed no noticeable
differences that I could see or relate to the UV breaking down/reducing the
iron or other trace elements. I can't see the lights causing that much
reduction to promote enough excess iron to be a problem. Heck, I'd like to
use this notion to dose iron for my plants:). Then I'd have one less element
to add.
Your 6700K bulbs do not promote algae anymore than a 4000K bulb does is my
point. That part of it is all hogwash for most folk's purposes. The
intensity of light is an issue that causes folks to think it is the color.
If you add more light to a stable set up you'll often get algae. This is
often what happens when folks add PC's or MH's to their tanks after being
use to 2 watts a gallon FL's tanks. Whoa! I have to add more CO2 and
nutrients now! It's not the color of the lamps that cause the algae. Amano
seems to have done quite well with his Blue 8000K or so lamps and gro lux
bulbs 8500K or so have been around for many years and other plant bulbs
which have done great for many plants growers. Do they have some "secret
sauce" or do I to prevent algae? No.

Regards, 
Tom Barr