I have a great deal of red algae at the moment in one of small tanks....It
is brush like and velvelty when in the tank - when its out of the tank its
slimy between the fingers - its almost a reddish purple in colour. When it
is dried in sunlight it goes a vivid purple colour.

Mine started when I switched the CO2 off........as I am moving evderything
to a larger planted tank and the CO2 unit had to be moved. Suddenly there
was excess Nitrates etc and the plant food (in the case of CO2) was suddenly
shut off - the algae started then and just took off even to the point of
clogging the internal filter.

I have not managed to get rid of it yet - nothing eats it (but I have not
tried Ottos yet - and probably won't bother now). Chemicals will not atack
it (that is none of the algae chemicals that I have tried). However, when it
covers everything it does look quite nice.

Martin