Refugium questions????

[beamer]

I'm currently running a 55 gallon tank with a canister filter. I want to switch to refugium and was wondering about a couple of things:

Best size for my tank?
Cost of refugium setup?
best media to use?
Maintnance?
Running lights?

How reliable is a CPR HOB refugium?

Every opinion counts! Thanks guys!

[Disher]

I had the small CPR HOB on a 12 gallon I had setup(overkill I know), and it worked really well. The flow was pretty wimpy from the stock pump that it came with but I was trimming Chaeto weekly. I didn't like how it hung higher than the tank, so if you're looking for something you can hide don't go with any HOB.

[beamer]

Ok so I made up my mind and I'm going to use a 20L for the sump. Now any opinions on pumps, overflow box, layouts for sump, skimmer, sump lights. I'm a noob at sumps so anything would help.

[reefreak]

I have a rio 2500
As a return pump and I have hob eshopps overflow everything is good and quiet