aeration

Question
i have a 90 gallon tank 4 foot wide 2 feet high 1.5 foot deep i currently have a 10 gallon aerator with a air stone on it and i also have a 2 foot wide air curtain the air curtain does not look like it is giving off enough bubbles at all they are very small and they don't appear on the surface does this mean it is time to change the air curtain i have a optima 40+ gallon aerator for the air curtain
thanks

Answer
Devin,
Is your tank planted, or do you use fake plants?  I currently have 2 10 gallon, a 55 gallon and am setting up a 90 gallon...I do not use any airation other than the HOB filter and there is plenty of O2 for the fish.  You should be fine with what you have unless you notice your fish "gasping" for breath and hanging at the surface.