if you already have a working sump pump that would be the easiest way.
Another choice is the safety siphon or something DIY like it.
http://jehmco.com/html/safety_siphon_aquarium_drain.html
there are 2 powered ones, just set the level you want to drain to and it does the rest.
Another choice is the safety siphon or something DIY like it.
http://jehmco.com/html/safety_siphon_aquarium_drain.html
there are 2 powered ones, just set the level you want to drain to and it does the rest.