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Re: photoperiods and algae

> Not only the canopy color, but also the canopy density of the trees change as
> seasons and colors of light do, brightness and darkness depending upon season
> in the Tropics. The plants growing under it learned to adapt to the different
> light conditions. Attempts in aquariums acknowledge this. Fact: Aquarium
> plants can adjust to the different colors of light (" mixed " colors of light
> over an aquarium are therefore basically possible). If one changes the color
> of light, then it takes however 3 - 6 weeks, until the plants adjust to the
> new color of light.

So can algae and they are better at wider range of attenuations.
> Give plants and fish a " midday peace ". Here is a tried and proven rhythm: In
> the morning at least 4 - 5 hours light. Then a dark break of 2 - 4 hours. (get
> a cheap timer) Afterwards at least 4 to 7 hours light. During the dark break
> the aquarium should not be completely darkened (indirect light of from windows
> or a lamp, a few feet away in distance). The light times should amount to
> always at least 4 hours. Shorter phases are not sufficiently used by the
> plants. In contrast to the general opinion we determined there are no negative
> effects, neither on fish, nor on plants. Probably because of strong light
> reductions, e.g. by thunderstorms, where in the Tropics they are relatively
> frequent.

The same can said for algae in the tropics. They too are "under the sun".
They've been under the sun much longer than plant for that matter. They too
live under leaves and other self shading attenuatations even without higher
plants. They are better at higher and lower lighting intensities. Some algae
can live at 800ft depths or in caves for that matter(a red alga, a few cave
entrance alga can live in moon light intensity). Some live smack dab on the
equator under full sun. Some live at 16000ft+ under thin air with low UV
protection and in places where no plant can survive.
> Algae do not like this " lunch time " obviously.

Well actually they do, otherwise the ones out in nature would not fair so
well. Try killing your BBA this way. They are exposed to the same problems
if not more than the plants are faced with.

Could the same result be accomplished by doing a blackout for 3 days
followed by normal photoperiod? It also kills/hurts algae.

>Whether that is because of
> the fact that the " primitive " algae are less flexible than the " modern "
> aquarium plants, or whether an improvement in oxidations - / reduction of
> equilibrium plays the main role, is not clarified yet.

Plants hold more enzymes. These enzymes pull nutrients into a cell. They are
directly proportional to uptake and activity of the type of enzyme. Many of
these uptake enzymes are very similar. If a larger algae(say a diatom) is
placed into a a medium with a smaller plants (say picoplankton) the diatom
will win at a higher nutrient concentration.
At a lower nutrient concentration the picoplankton will win. They need less
to live and less to start up and grow. Throttling the light on/off may
simply be taking advantage of this fact.
> Against algae this
> method works astonishingly well. (in the first days after the conversion you
> should measure the CO2 regularly and adapt the CO2 accordingly. Usually less
> CO2 is needed).  Read about algae on the Tropica site, that is a good
> companion piece to this info!

I'll take a look. Okay, I could not find it. I did like the part about the
sinking Riccia lacking aerhyncyma and as a wintering over defense to
freezing at the surface.

> Also, experiments by this research team show  that light with low to medium
> blue, medium yellows and greens, and high reds give plants optimum growth.

This is old hat. This was shown many years ago.
> This is due to the way plants grow with light diffusion, another story in
> itself! 

I am curious as to why folks do not believe algae are not exposed to same

(The All Glass compact flourescent strip lights are as close as it
> gets, 55watts and 96 watts). A German company did the research, I had to
> translate the results and rewrite this in english. Their method works for me!
> Don

A nice test for this notion would be a set up where a single tank has a flow
through but one side has the light that goes on/off in the same cycling
sequence that you suggest and the other side has normal photoperiod as your
control. Both side have the same everything else so the only difference is
in the lighting of each side. A 4foot tank divided into 2 ft sections would
be a suitable tank. A porous shade for removing any light spillage would be

This would tell you if this works. Then try the "3 days off" blackout method
to see if this is any better. Analyze the results. Try other combinations.

I have a big problem with this whole method in the first place. Nutrient
management can take care of much of this. Why is there algae in the first
place? Poor balance between the light/CO2/nutrients. By manipulating with
one part, the lighting, you must keep good tabs on the the other(nutrients,
CO2 etc). Was this done?

How did they induce the algae to begin with? Could they have gotten the same
results by keeping a stable nutrient level in a good range?

Thanks very much Don. Interesting and worth looking into. You've raised some
good issues. Perhaps they've addressed the issues I've raised. If not, I am
skeptical. I could not find the page you mention though. Link?

Tom Barr