Thanks. I think it may be cyano
; as malkore said, it looks like the bubbles are prolly under that top sheet of algae. When the algae collects into a blob (when I clean it), it is a dark green colour.
Hmm.. what should I be doing about this problem? I actually have nothing connected to this tank except for a heater now. I've removed the filter, and rely on my roomlight as a source for light as the only thing I have in there alive is the betta and the java moss. From memory, should I be doing a total blackout of the tank or something like that to try and fix the problem?