sump and skimmer question

[keith gray]

I have 2 questions for anyone:
1. Have you ever bought a used skimmer ? I am a little reluctant
2. If you build a refugium how big should it be ? 1/4 as big as DT, 1/2 as big as DT ?

 

[flukes]

Yes I have bought a used skimmer. The only parts that ware out on it is the power head and that can be replaced.
Build the sump as big as you can!