which is better mud or sand?


New member
Hello all,

I just built a sump with refugium and am debating what to put in the fuge....rubble, san, mud, any combinations of the 3 and in what quantities? The refugium portion of the sump is 16.5x10.5x12 and it will be used on my 55 gal system. Total sump volume is 26 gallons...of which 20 is used making the total system volume right at 75 gal. All your input would be apreciated..thanks alot!