I just built a Sump for a new set up. I am very new at all of this and beleive that we learn better by doing. I did my research and thought how I divided the Sump was ok. Now I am having doubts. I'm planning on a reef tank (size is 55g). The sump size that I built is 36"l x 10"w x 16.5"h. The skimmer section is 9"x 10" x9" (4g) the refugium is 9.5"x10"x12" (5g) and a return section is 15"x 10"x 9" (5.8g). I am worried that the refugium section is to small. Am I in the ball park? Also I just read about making a refugium look very eye pleasing with the right "plants ect.." I have a hang-on Refugium (CPR 24") that may be able to piped to a area in the open if needed, but would rather not go that route if I could avoid it. Thanks for all your help.