I built one for Delfin, which given her fuel capacity seemed like a pretty good idea. *I needed pumps to transfer fuel between 7 tanks anyway so the polishing was a bonus. Here's some poop on what I built. *The only difference is I have replaced the 24vdc pump in favor of the much quieter and more efficient 120 vac pump. *The carbonator pumps seem like the way to go to me...
http://delfin.talkspot.com/aspx/m/556668