I have yet to have a tank myself that doesn't have some sort of agitation from the filter being used. Therefore I have found air stones to be unnecessary and more an object of aesthetics.
It is true that with enough surface agitation from a filter air stones are not NEEDED. However, like with filters, more is always better. You may have enough aeration from the filter to keep the fish from gasping at the surface, but that doesn't mean it couldn't be better. The other issue is that if that filter ever stops then what? Like I have said before, I have seen tanks saved when the filter stopped because they had air stones, and others lose fish within hours because they didn't.
I forgot about hydroponics, another example of bubbles themselves actively aerating.
Seeing as my current filter is basically a modified airstone (sponge filter) I don't think it really matters...
I'm also a proponent of running multiple filters on larger tanks anyways. So unless I have the worst luck ever and every filter decides to stop at the same time then I think I will manage...
Don't you also have heavily planted tanks? These help tremendously with filtration, and also, airstones are not recommended in a heavily planted tank except perhaps at night.So unless I have the worst luck ever and every filter decides to stop at the same time then I think I will manage...
Don't you also have heavily planted tanks? These help tremendously with filtration, and also, airstones are not recommended in a heavily planted tank except perhaps at night.