jus to add on, the sump consist of 4 compartment. being 6cm, 8.5cm, 8.5cm, 6cm. you can actually convert the 2nd and 3rd compartment into a refugium if u remove the dividing glass panel. which will add up to a total of 17cm for the refugium. A diy egg crate rack + splash box with acrylic cover will also be included.