Relatively new to hobby. Just picked up a used Red Sea Nano 20 gal. I currently have a waterbox 25 and is going great. I have never had a sump/protein skimmer. I have it placed in the middle where it goes and the box on top with lid. I have the gate all the way down. Is there supposed to be water in the box. It is dry. There is power as I can feel vibration but have no idea if it is working. Have no problem buying another if it is broken or upgrading to something different. And advice would be great.