What air tube are you talking about? Did you mean, attach something that will create this venturi-style microbubbles into your tank? Aesthetically for me, I don't like the microbubbles because it makes it seem as though the tank is cloudy.
I used to have an air pump that pumps bubbles in the tank. That seems to make the water clearer for me, I dunno why. The only thing is, salt formation start showing up outside of my tank's canopy. Sometimes ALL OVER THE PLACE too. Without the airstone bubbles now, there seems to be a very thin protein oil thingie that you see on the surface (even though I have a skimmer). But I resolved the salt stuff that I see outside. Just a good powerhead in your tank should be fine.
But I don't think you need to have these microbubbles to have a successful tank.
Also, what I do during water change is put the powerhead in the bucket of water, put airstones in there, then the salt. Then let it run for a whole day.
I don't know if this post helped you at all. I just don't understand the "air tube" yet.