ProFlex Sumps

[Bucknutz]

Recently picked up a ProFlex Model 3 Sump and have a few questions.

http://www.aqueonproducts.com/products/proflex-sump.htm

• Any experience, or advice with this sump?
• New to filter socks. How often do you change them?
• I added a 4" sand bed, and a little bit of live rock to the refugium. What should I put into it now? I was thinking about doing one of these packs for the refugium. suggestions? http://www.reefs2go.com/category/sea_life.all_free_shipping_packages.refugium_macro_packs/