Calcium Reactor 618 All cell cast acrylic construction Clear lid to view proper O-ring seal Key hole slot for lid removal Micro ball valve effluent control Eheim 1048 pump, bolted to base plate pH probe port in lid pH probe adapter included Auto fill bubble counter 10 x 9 foot print, 24" overall height Holds 12 pounds of media, we recommend large grain schuran type For reef aquariums up to 350 gallons