Proper water inlet level?

IME, the water coming in should be high enough not to disturb the
substrate, and not too low to provide surface agitation, which
promotes gas exchange.

b

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"Robert" wrote in message
...
Is there a "best" level for the water inlet to an aquarium?
Specifically, does it matter whether the inlet is above or below
the
water level.? Could you please tell me the pros and cons, (if
any)?

(For simplicity, please assume that all filtration (both mechanical
and biological), and aeration take place outside the tank, and that
they are all "adequate".)

Thank you very much,
Robert