have a 135 gallon soon to be reef tank. No corals yet, just getting it stood up. Had a 55 15 years ago but didn't have the time to invest. Now retired and getting started. have 5 fist and about 60 lbs of rock and a sand bottom. Hired the fish store to set the tank up but didn't talk about a Refugium. but seems the right thing to get started on. Had a bit of an ugly stage but not real bad, scrubbed the rock and messed the sand up a bit and the filter system cleared it up. Good numbers but a bit high phosphorus (.2). Trying to do 10% water change every other week. I have a 4 compartment sump with the back compartment filled with 4 socks and the flow comes from there to an empty space where I have my heaters, then to the skimmer and then to the return. so I have 2 questions.....1. can I put the fuse before the skimmer or do I need to move the skimmer to the empty section? 2. can I leaved the heaters below the Cato or do they need to go in the skimmer section?

