Blue-green algae

Some interesting (I think) observations:

I had a bout with blue-green algae.  I think the following
brought it on:

  o recommended dosing with an expensive plant fertilizer
  o long photo-periods (forgetting to turn the lights off
    at night).

The blue-green algae would first form on the roots of
a terrestrial plant sticking out of the tank, but would
then "fall" down onto the aquatic plants below.

I reduced nutrients and did water change, no avail.

I shut off the lights over the weekend, and came back: the
plants are fine, and there is NO blue-green algae.  There
was some very low ambient light, but nothing significant
over the weekend hitting the tank.

The tank has ramshorn snails and one female betta splendens,
(the betta definately won't eat algae).  The water is pretty 
soft (22 ppm Ca/Mg).

I have repeated this experiment twice.

--charley                           Fort Collins, Colorado USA
charleyb at gr_hp.com	or	charley at agrostis_nrel.colostate.edu