could a 44gal rubbermaid container function as a sump? just have the the pipe from the overflow run tnto the container and put the return pump in the container? or is a real tank just a better coice? its for my 55gal.

You could use a rubbermaid, but you have to be careful. I had 2- 20 gallon rubbermaids that I used to mix my water. Both of them only lasted a few months and started leaking. That would destroy your tank and make a huge mess. I would go for a real sump or fuge.