Posted: Fri Apr 18, 2014 10:28 am Re: water surface oil-like slick or film
{ aaah, this post happened immeadiately after the duck's post, so there is overlap in the posts and I think he answered my questions }
when I google "fish tank aerator" I get lots of info and different types. Given that there is no livestock in the tank (other than an occasional minnow awaiting his turn to join my RES at the dinner table) I don't really think I need water aeration. So is it just for the bubbles breaking the surface tension that you recommend an aerator?
I do know that if I point my cannister filter's output stream so that it ripples the water suface then the oily/film (or whatever it is) doesn't form. This is a ban-aid, and doesn't answer what it is? I don't want whatever it is to chemically harm my RES!!!