I have a aqueon 14 gallon tank laying around ( same dimensions as a 10gallon but taller) and want to make it into a sump for my 55. The first chamber is a BRS Filter sock mount with my heater and the second chamber my reef octopus nwb110(10.1x6inches) and a pump for my BRS media reactor. My final chamber is a return pump and my auto top (which is either jbj or aquascape or if I have money Tunze oslmolatior) [recommendations plz]. What dimesions should i make the sump.... Thanks for your help