Rebuilding hardware set up

[jassz]

Thanks all.

By 'they' I meant people that design aquariums. As you said, they have to be able to handle the situation of a power outage with out flooding 100+ gallons all over the floor. On the other hand, when I tried it and the sump was filling fast, I panicked and turned the pump back on.

pterfloth, when you say remove the return line from the tank, are you referring only to the one that leads from the overflow box? What about the one that leads to the Fluval filter?