I am in the process of changing out my orig wet/dry drip filter (built myself) in a 29gal sump with a refug. From reading I think thsi is the way to go so my macro algee gets a chance to live (yellow tang goes nuts over everything I put in the 75gal). The question I have is should the skimmer go internal or external? From reading here it seems like most of y'all go internal to the sump. Right now I have a mag9 returning to the tank and a mag7 that was going to supply the skimmer. As I read that also seems like an error on my part. I *think* that I should have the skimmer in-line with the flow into the sump. This is all new to me, right now I have a cheapie store bought skimmer in the sump that constantly causes me problems with the bubble level into the cup. PS. So far I have found about three different ideas on here that I want to try and a few tips that will also come handy. Very nice site. erick..