sump

[Jack]

What size main tank is it? Mag 7 seems small after head pressure.

5$ rubbermaid sumps work, but some people prefer modified glass aquariums or custom acrylic sumps with baffles. Either or works.

I would say that it wouldn't hurt your tank at all. Make sure your parameters are close and turn it on. Adding extra water volume is a good thing! Think of it as a water change but you're adding water to dilute the nasties

I'm sure they will be lots more replys so ask away!