What is the difference between a sump, refugium, overflow box?

[bethany]

Help me out please, still learning! All i have is a protec 60 gallon wet/dry filter and lights. Also, how often do i clean or change my filter pads??? My tank is about 4 months old and they don't look dirty enough to me...

 

[viper12775]

the diff between the sump refugium and overflow is the sump holds extra water making your tank more stable and provides a place to put your skimmer heater and probes ect. the refugium serves for a place to grow macro algae to cut down on hair algae in your main tank and the overflow is a way to drain the water from the main tank to the sump wet/dry or refugium and as far as the filter pads i change mine once a week before they start turning into a filter