I'm in the process of setting up my refugium/sump on my 55g. In the 1st chamber I'm going to have an Octopus NW-150 skimmer, 2nd chamber will be the return pump, a Mag 9.5, 3rd chamber will be the refugium with chaeto. I'm planning on having a bubble trap between the 1st and 2nd and a single divider between 2nd ans 3rd. I'm going to try and plumb this thing a simply as possible. Water will enter from a LifeReef siphon box (600 GPH). The return line will have a "tee" in it, with one end going to the DT and the other going to the refugium. I understand that I'll have to throttle back the return from the 9.5, but do I need to put a ball valve before the "tee" or do I need to put one on each of the lines after the "tee". Also, any recommendations on my flow rate is much appreciated, I'm going to have 2 Koralia 2's in the DT. Plan on keeping anything except SPS. Thanks.