Finally I see some water is running, not really salted water yet but there is something to look at for now ...
I have the same Eheim pump just like you. I think if you use vinyl tubing instead off the pvc pipe and use a mouse pad to put underneath it, it will reduce the vibration humming sound from it. Maybe not a big deal for you, but my tank is in my bedroom so I am very fussy about noises. I try to reduce any unecessary noise as much as I can.