Just a thought here - I don't intend on keeping any inverts in my 150. So while I've been running over design ideas for my hanging wet/dry setup, the thought crossed my mind to use copper tubing for the spray bars. Originally I was thinking nylon or pvc, but then I thought copper because it is cheap, easy to work with and could possibly act as a persistent preventative for waterborne parasites such as ich. 90% of households in north america are plumbed with copper, which most of use use to fill our tanks with with no copper related ill effects. As I said, it would only be several 12-15" sections of 1/4"-3/8" copper tubing and the rest will likely be plumbed with plastic hose.