i currently have a 910*325*325 display tank with a 75l sump.i purchased my return pump according to riaan 1800l/h, a vibration pump (5000l/h), and hydrometer.i need to no what protein skimmer would be best internal or external.i want to go 4 external as my space is limited.i know u guyz replied already but posting in one thread would make it easier 4 u guzy to help me.thanks again nemoit makes sence.