Need Korallin C3002 Setup Help

[Spudroach]

I need some help. I just bought a Korallin C3002 and set it up next to my sump. Being that my sump is in a different room than my aquarium I was going to pull the inlet water from the sump and run the return water thru my skimmer (it has a fitting for that purpose). I can't seem to get the included Eheim pump to pull the water into the reactor unless I fill a bucket with water and put it above the reactor. The directions say a second pump is not required.

Can anyone give me some advice or have experience with this? I can tee off my main return pump to provide extra pressure if need be, but I don't want to over power the reactor.

Any input would be appreciated.