i dont think adding sand will benefit this type of sump if im not mistaking. for u to have an effective sandbed it has to be 3 or more inches and based on the size of the fuge cus of the size of the tank ur going to run into problems if im not mistaking.
Haters dont really hate you, they hate themselves; because youre a reflection of what they wish to be. GFYM
This was my 10 gal sump/refugium. Worked perfectly. This was designed to fit a BM NAC 3.5 skimmer. This was designed by Rkaragozler.
Just adjust the measurements and baffle height to fit your skimmer choice. If you are gonna have an ATO you can even cut down the size of the return section so that the refugium is bigger. if you have any questions about it let me know.