A sump is a great way to filter - it gives a much bigger filter volume...
Unless you're desperate to not spend any money, I would recommend using a simpler Eheim pump to move the water around.
I've got two of the Eheim Compact pumps, 1000 lph model here
. They don't produce a whole lot of head, but are OK for "low-lift" applications. When I bought my second one a few weeks ago, I think I paid £22. [One of these pumps is used to circulate the water in my water-storage in the fish-room, which is 2 x 25g "loft-tanks", which are connected by a 15mm connection [and a 15mm "full-bore" quarter turn ball-valve], and if I set the filter to "max" circulation, it overflows the recipient tank, because the 15mm pipe is too restrictive - admittdely, that's not a whole lot of head, the tank is about 650 mm tall - but it gushes out pretty quicklyeven when the tank is almost empty].
For more head, use the Universal
pumps from Eheim. I haven't used these myself, but the LFS I do most of my business with have them in their sumps (including the display tanks that are custom made).
Caveat emptor: I haven't build a sump yet, so if it floods your house, don't blame me.