StringerBell wrote:
What does it mean if the Skimmer is not producing foam? (Its not
broken,sometimes it does,sometmes it doesnt.)
Does it mean that at that particular moment there is very little
free-floating dead organic matter in the tank?

Yep.

Is this a sign of improving water quality?

Sort of. It's not really connected to the current level of nitrites, nitrates,
etc. in the tank, but it does indicate that the ammonia and nitrite levels will
drop soon.

George Patterson
All successes in conservation are temporary. All defeats are permanent.