I will soon be setting up a series of DWC beds.
A few questions about DWC that i cant find clear answers for regarding water flow.

Can i use my sump tank as a mineralization tank as well by adding an air stone to increase DO?
Would it be acceptable for me to flow water from fish tank -> swirl filter -> mineralization/sump -> bed?
Is the sump tank necessary at all? if so what volume of tank would i need for a DWC bed of 1000L matched with a fish tank of 1000L?

Finally how do i know how big of a swirl filter to build, ive been reviewing this guide on building one, would this be sufficient size for a 1000L tank with average stocking density?

http://www.earthangroup.com.au/diy-back ... rl-filter/