Well, it can mean either.
I suggest being proactive and staying on top of things.
I've routinely had tanks without algae(eye visible) using several methods(CO2
, non CO2
However, we all mess things up, or do not do something or another at some point.
No big deal, you take care of the algae issue, clean, work hard to get thuings back and then things are more stable thereafter and you keep up on it.
Some seem to think that a nice scape and high light and CO2
should balance easily and require no to very little work. This is not true, it might happen for a period of time, but at some point you have to do some real work.
So you do it and then do not worry.
Same old thing.