Beautiful setup you have! Is this a new setup? Im not sure about the surface skimmer though. Dont think its quite baby shrimp safe though i know the water surface is gonna be sparkly and clean. Otherwise, i have read it can suck babies into it. You may put a fine mesh over it but that would render it inefficient. To take care of the oily film, i find increasing surface agitation from the filter or an air stone to move the water quicker into the filter works. Oil skimmers are abit dangerous. Otherwise that is a nice tank! So this is what i do, initially when i was using a sponge filter like you(cant really see, or is that a foam over the intake of a hob filter?), so i would find the dead spot from the top(water area not moving) i would put the air stone over there, so when the bubbles rise, the water is moved and than the filter can get the water there. You wanna form a circle current (at least thats what i call it), doing the airstone will move the water and if you adjust the filter intake strength accordingly, you can actually see the film disappear quite quickly from the top. Its unavoidable especially in a planted tank i think(the film) Especially if the co2 system is non solenoid regulated(diy co2 setup), you need the surface agitation at night else carbonic acid can build up in the tank. Shrimps love oxygen thats what i observed. *love the moss structures* looks adorable Sent from my SM-N950F using Tapatalk