Bio-Fil 1 This filter box contains no bio-balls allowing you to use your own choice of bio media or existing bio-balls. This is an excellent choice for coral reef tanks using the Berlin or Eco-System methods of filtration. Its design includes an expandable sump to accommodate protein skimmers or other filtration accessories. This filter includes a post filter sponge, and fits most pre-filters. Select your choice of inlet bulkhead size below. Built with quality craftsmanship and of rugged acrylic construction make this unit easy to install and durable. Note, models 182, 240, and 360 have two each inlet bulkheads. Gals L x W x H Bulkhead Price 60 g 20 x 8.5 x 16 1" 1.5" $183.25 125 g 24 x 12.5 x 16 1" 1.5" $214.50 180 g 30 x 12.5 x 16 1" 1.5" $259.50 182 g 30 x 12.5 x 16 1" 1.5" $274.50 240 g 36 x 12.5 x 16 1" 1.5" $275.25 360 g 36 x 12.5 x 20 1" 1.5" $367.25