by PsYcHoTiC_MaDmAn » Tue Jun 03, 2008 8:26 pm
canisters do not give off oxygen.
the oxygen enters the water through the surface, therefore the more surface the better, and the best way for that is surface movement. the ripples caused by the filter outlet will usually be enough to provide adequate oxygen for a reasonable bioload.
much higher bioloads will benefit from the superior biological filtration method of a wet/dry tower. which will HUGELY increase the surface area of the water, meaning much higher oxygen content