dark period

Stephen Pushak wrote about a dark period

Stephen mentioned 4 (four ! ) dark days as an experiment.

I am afraid your plants cannot sustain many of such dark

From Dennerle books I subtracted an other sort of "dark

It's on a daily base:
 - mount a proper amount/sort of light
 - light on for 4 hours
 - light off for 2-4 hours (2 hrs. seems to be too little..)
 - light on for 6-8 hours
Total:10-12 hours of light within a period of 12-16 hours.

The more "basic" algae should not be able to adapt to this
scheme; the aquatic plants should (It was tested!).

Your plants should NOT react to this, or they might suffer
too much (I think they did in the experiment you described)!