now just how I think...
IF you are using the bubbles to create turbulence to clean your bio-film then more is better....
If you are just using a difuser to saturate the water with oxygen then you have a whole other set of variables everything from pH through water temp to depth f bubbles are discharged to this to that to to to... then one will give yo almost saturation, and you don't need 100% saturation.
Also just how much of a fish load is a key aspect to consider... think you could do with less.
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