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Re: Low light



> From: Aquatic-Plants-Owner at actwin_com (Aquatic Plants Digest)
> Reply-To: Aquatic-Plants at actwin_com
> Date: Tue, 2 Oct 2001 15:48:01 -0400 (EDT)
> To: Aquatic-Plants at actwin_com
> Subject: Aquatic Plants Digest V4 #1317
> 
> 
> I am very glad to see that other people also realize that you do NOT need 2
> watt/gal to grow plants.

It is not so much the fact you don't need X amount of watts etc. That's
pretty well understood from experiences. It's more that the excess
nutrients(NO3, PO4, Fe etc) are still present and work well at low
light/medium light and high light levels provided that the CO2 is in a good
range and the nutrients are kept in a decent parameter range.
That is some what a new notion.

I had assumed that at much lower light levels that these nutrient levels
would need to be changed. It was not so much the levels themselves but the
frequency of dosing(longer in between the next dose but much less than I had
assumed also) that was the only change. The target levels where kept the
same.

This means that no matter what your lighting levels, the parameters of
nutrients can be the same provided the CO2 is also the same good
level(20-30ppm). You'll still get nice growth with no algae problems and it
can be a good method to stop algae problems and lowering the light/or
blackout is a cheap method for control. After the plants get a good foothold
again, increase the lighting back up. Nutrients/CO2 the same. Plants will
use the nutrients up faster so we'll have to add then faster as the lighting
goes up. But this can really mess with the algae. It also would let
herbivory become very effective vs algae growth rates during this period of
low lighting. Low/less lighting, not less lighting period. These are not the
same thing. You can raise the lighting back up later when things are
better/get back from vacations etc.
Regards, 
Tom Barr