Im struggling with that, in normal submerged use, the lily causes a slight wave/ripple (im not sure if thats enough to oxygenate the water) or if I have it sat a millimeter below the surface or anywhere higher than that it gurgles loudly because it creates a loud bath type vortex which is surely not how it is supposed to be installed??If you add more surface agitation you get more O2 and can add more CO2